Most of the mods I use are utility and convenience mods... here are some of my favorites:

= Todo List - don't know how I ever lived without this mod, which I use to keep track of what I need to do next... absolutely essential for larger bases. I really wish it could be used 100% from the keyboard, but it's still good despite requiring the use of a mouse.

= Angel's Addons - Storage Options - the only one of the Angel mods I use... it gives me much larger storage containers, like warehouses, so I don't have to bother with the annoyance of dealing with lots of tiny containers

= Attila's Zoom Mod - lets me zoom much further out than the vanilla game does, also lets me view specific positions on the map very quickly and reliably

= Auto Deconstruct - marks drills for deconstruction once the resources they're mining run out... just a nice little convenience mod that stays out of the way 99% of the time, and simply makes the game just a little bit smoother in that I don't have to manually find any of the drills that need deconstructing

= Belt reverser - quickly reverse belts... saves so much time. This should really be in the base game.

= Bob's adjustable inserters - a quick and easy way to adjust where inserters pick up and drop off to... should also really be part of the vanilla game

= Closest first - make construction bots build and deconstruct close things first.. don't know why this isn't the default

= Even Distribution - super useful way of quickly distributing resources over many consumers, instead of loading resources to one consumer at a time.. should also be in the base game, imo

= Exploration Vehicle 1.1 - lets vehicles run over and destroy trees and rocks in the way

= Explosive Termites - quickly destroy annoying trees. There's a Tree Deleter mod I used to use until it stopped working. That was good too, and even faster than the termites.

= Far Reach - some might consider it cheating, but I just find it annoying and a waste of time to always run back and forth across the screen to do something... this lets me do it from anywhere on the screen.. with a zoom mod, my reach becomes even greater.. both of these together with some turrets make fighting vanilla biters too easy, so if you want to fight biters with this combination I'd recommend using a biter enhancement mod like Rampant to make the biters more of a challenge

= Fill4Me - auto-fill items with fuel/ammo when you place them... very convenient. See the above note on the Far Reach mod, as this is another mod that together with Far Reach and the zoom mod makes fighting the biters too easy.

= Ingos Advanced Start - gives you a bunch of bots and an exoskeleton to start with.. I love this, as I really don't enjoy the slow speed and slow construction/deconstruction rate that I'm stuck with in the early game... this lets me get to the fun parts of the game faster. Not recommended for one's first playthrough, but I find it essential afterwards.

= Inventory Repair - uses repair packs auto repair items in one's inventory.. another nice convenience mod that just does the right thing without interaction

= Laser Lines - super useful for aligning stuff perfectly

= Land Mover - dig holes to make landfill... with the Far Reach and a zoom mod using landfill will let you make 100% secure barriers against biters. Some might consider this cheating, others a welcome relief. I just turned off biters completely eventually, so it doesn't matter to me now, but the mod is still useful to me for crossing lakes and the like.

= LTN - Logistics Train Network - not an easy mod to learn to use, but totally worth it for large train networks, and my favorite of mods of its kind, but I'd use it with LTN Combinator and LTN Content Reader for more convenience

= Miniloader - very quick loaders and unloaders that don't impact UPS nearly as much as some similar mods

= Nixie Tubes - a nice way to display info about various signals

= Power+: Power Utilization Meter - adds signals showing useful information about your power networks

= Splatter Guard - keeps you from being run over by trains.. there are a bunch of other mods like this, which I haven't tried... probably anything that does the same thing will be good enough

= Squeak Through - absolutely essential mod that lets you walk through tight spaces you otherwise couldn't

= Train Network for Players - an easy way to call a passenger train to your location

= Vacuum Cleaner - quickly pick up stuff on belts or from the ground.. much more convenient than the vanilla method

= Where is my body - shows where you died... lots of mods to do this sort of thing.. any of them are probably good. Something like this should probably be part of the vanilla game too.

I use many, many, many more mods (over 100 in total).. but this should be a good start for just about anyone.

I've also disabled biters in my games, because I just find them annoying at this point, but when I had them enabled I also liked to use the Rampant mod to make them more challenging, and a bunch of improved weapon mods like Modular Turrets, which I remember liking.