[Windows Phone 7 Q&A, Help & Troubleshooting] link68759:
Before I get into my list, I'm just going to run down how apps and multi tasking work on WP7 in case you don't already know.

#1: No app can truly run in the background. The only way to get an app to continue running is either to have it up and prevent the screen from turning off, or (if supported by the app) allow it to run under the lockscreen, which means when you press the power button, only the screen turns off, the phone does not enter a sleep state.

-----------------The exception to this rule is when an app is playing music. If the app dev has done it correctly, he should have handed the music playing off to the system, so once you set up the music source in app, you should be able to minimize it and use the next/previous/play/pause controls. In fact you can even go to grooveshark's beta html5 in internet explorer; HTML5 can plug in to this system media playback! I was very excited to learn that. But at least on grooveshark, next/previous controls don't work.

#2: HOWEVER each app can have a "daemon" which is essentially a set of tasks that are run periodically by the system (minimum of every half hour). So if you use google latitude, latitude apps will only be able to update your position every half hour (or at longer intervals, but no shorter). This system of background daemons is actually very very good as it encourages unique thinking from the developer side, and still gives the user the benefits of true multi tasking without the battery drainage. What a daemon can do isn't that limited, but it's the fact that no internet connection can remain active in the background that poses a lot of problems (for example, IRC clients cannot have multi tasking for this reason). Since things can only run every half hour, you don't have to worry about things like turning off your gps, since nothing is allowed to just turn on the GPS and keep it on.

#3 : Also there's still push, of course. Lemme break that down for you: push notifications can either be through the live tile (rather than having a background daemon update the tile, things are pushed to it immediately as they arrive), or push can be used through statusbar notifications. One unfortunate oversight in this system is that if you have an app that you do not pin to the start menu, and if it has a notification and you did not hear it... there is no list of missed notifications. This doesn't come into play that often; for me it only happens with eBay, where I don't want to bother having that on my start screen but I might miss some alerts.

#4: Battery Saver mode is YOUR FRIEND. You can get nearly another day out of your phone (or I can with my Titan) when battery saver kicks in. You can enable it so that it turns on when the battery is low (%20), or manually. However, it disables all background daemons and push notification in order to save battery.

#5: Multi tasking and switching between apps. Hold down the back button to see the list of the last several apps you used (or in the case of my unlocked ROM, all of the apps you have used since boot). When you minimize an app (press the start button), it gets "dehydrated" which means it's just suspended to RAM. It works like you'd expect; start typing something in one app, switch over to another to look something up and switch back to the first to resume typing. To remove an app from the list, or "exit" the app (since it isn't actually running the only thing this does is remove clutter or perhaps free up some slots), you "back" out of them. Press the back button until the app goes away.

One of the reasons, in my opinion, that windows 8 is getting a lot of negative flack is because people don't know that live tiles are good. It doesn't help that, last time I checked, there were no useful live tile apps in the 8 marketplace yet. So frustrating! People hate what they don't understand, because hating on the internet is the standard state of existence. I encourage you to think about what you do on the internet every time you sit down on your computer, and see if you can find an app with live tile to do it for you. For me, I had a routine of checking my email(s), going through a lot of webcomics, reading news feeds, etc. That was my daily routine. Now with WP7, I have each aspect of my routine as a live tile, so I can literally replace that entire process with just looking at the start screen.

The other thing about live tiles and metro that people fail to understand is that active push notifications, where unnecessary are BAD, for a few different reasons. Push notifications are "active" and live tiles are "passive". This is because live tiles do not make any noise or otherwise prompt you to look at them; they are simply there and deliver content when you pull out your phone. Let me put this in perspective: say I pull out my phone to look up something on wikipedia. I can see that I have 2 new emails, some new RSS articles and a facebook notification. Number 1: I don't feel the urge to go and clear the unread count of all of these things, as I would if they were all aggregated in the statusbar like on android (because you need that statusbar for things, and if it's cluttered and you don't keep up on it, it quickly fills up and becomes overwhelming). I can leave them alone for now and go to wikipedia. Now if this were an android/IOS device, I would have gotten an audible notification for each of those three things, and I would have taken time out of whatever I was doing IN LIFE to tend to my phone.

Some points about stressors here (and when I say stressors, I don't mean overwhelming stress you can feel, but stress in the clinical sense, which is objective): having your phone beep at you constantly stresses you; for most people it's difficult to put their phone out of their mind until they have seen what the notification was. This is not good.

Moreover, feeling the need to go and clear unread counts/managing your statusbar is also somewhat of a stressor; if it starts overflowing you'll either learn to not use things that create notifications (somewhat limiting your experience with a smartphone), give up all hope and never look at the statusbar again, or just clear it out and miss out on things you wouldn't have if the information was presented in an orderly fashion.

Live tiles, being passive, are also more efficient in terms of time spent on the phone and your phone's battery life. Notice how in my example, I observed the new content only when I was already pulling out my phone to do something else. With things aggregating in bulk, I can view them in bulk at points of the day where I was already on my phone. This is opposed to pulling out my phone every 15 minutes because something new happened... which wastes time pulling your phone out of your pocket many times a day, wastes battery when turning the screen on/off many times a day, and if you use wifi; wastes even more battery when the wifi radio is turned on/off sporadically many times a day.

So yes, live tiles are an objectively less stressful approach to mobile devices :D and less distracting from tasks at hand. The same concepts can be applied to windows 8; rather than having popup notifications for all your facebook, email, rss, etc bombard you while you're trying to write a paper... all of that information is silently aggregated for you in the background.

------------The List-------------------

For alarms,

627.AM

Built in Alarm app.

For task / project management

Tasks by telerik

Or just use the built in calendar app

Or use Onenote and Pin your task list to the start screen.

For RSS

Wonder Reader hands down, none of the other google reader clients are quite as fully functional and polished.

Fuse is pretty but I never got the hang of using it.

For Wifi Video calls

Tango. It's pretty limited in that the android and IOS client are updated with better features, and you can only call other people with tango... but the service itself is more efficient and more reliable than the skype app was last time I tried it. Moreover it supports push for accepting calls, something skype doesn't. Also I like the concept of not having "online / offline" states. You call someone, and they choose to answer it or not. Why would I need to log into a phone...

I used to take notes on a tablet at school, and ran into the same problem as you. Only solution I know of is to print your notes back into onenote. You'll have duplicates of everything unfortunately.

Podcast functionality is built in.

For random recommendations...

das Image (Better image search)

Image Map (Renders all of your pictures on a map based on GPS loc info)

Dynamic Background (Unlock) (Updates the lockscreen picture every half hour choosing randomly from a pool of selected images)

Battery Status (Unlock) (Live tile for current battery percent, also tracks battery usage and graphs it for you)

EnClock (there is no stopwatch built in to WP7, and you never know when you need one)

eBay

HandyScan (Helps you take good pictures of papers, backs up to skydrive. Better to keep documents in here than with regular pictures).

Keep Alive (by jaxbot, it prevents wifi from turning off)

Nokia Drive (Unlock unless you get a nokia device)

MetroPaper (Read it later / pocket)

Metrotube + Supertube (youtube apps. 1 is awesome, 2 lets you download videos and even create offline "music" playlists)

Photo2cloud (back up full res photos to skydrive independent of PC)

Supreme Shortcuts (Unlock) (Lets you pin any setting page to the start screen)

WeatherLive (There are plenty of other weather apps... but weatherlive works, it's incredibly thorough, updates live tile using GPS location, is pretty, etc)

Zite (Gives you news articles based on google reader feeds and who you follow in twitter, good for every time I go to the toilet :D )

If you use IRC or SSH

The SSH Client Pro

TinyIRC

And now that you are a part of the WP community, you should invest in AND pin the live tiles of each to your start screen:

WPCentral

WMPoweruser

Games! I Don't like to play serious games on my phone; I like something I can whip out at any time and turn off at any time, no consequence. That said, I make an exception for the Final Fantasy updated / rerelease for WP7

COLLAPSE (Probably my favorite mobile game. It's an easy puzzle game, but satisfying to plow through at ludicrous speed. There are some very hard rounds with special conditions though.. story mode is dumb but it has unique challenges and you need to play through it to unlock all the quick play modes).

Final Fantasy

Wordament

Fruit Ninja

Dodonpachi Maximum (Genre: Bullet Hell. If you don't know what that means then try it before you buy it. If you love bullet hell; buy this. It's by CAVE).

Wizard's Choice (A casual text adventure).