[Sony Ericsson XPERIA X10 Mini] bojler:
After flashing regular MiniCM9 there are only left ~11 MB in the System ROM internal memory, so I wanted to free up some space. Other thing that I had in mind is that android is running many background apps that I don't use. And by removing them, there is also freeing up some RAM.

Before starting anything make CWM backup.

You can use one of the 3 methods to remove unwanted apps:

a) in windows, you can open downloaded MiniCM9-3.0.XXX.zip with WinRar or 7zip and remove unwanted apps in system/app folder. After that move modified MiniCM9-3.0.XXX.zip to sdcard and flash via CWM,

b) using a Titanium Backup app and delete them there, OR

c) use Root Explorer app and navigate to system/app and remove unwanted apps.

I always delete following apps that I don't use. Browse the list, and delete ones that suits you:

ApplicationsProvider.apk - Provides the list of installed apps to Play. Fetches the list of applications installed on the phone to provide search suggestions.

Browser.apk - There are better alternatives such as Opera or Boat Browser

CMUpdateNotify.apk - I am really often on xda and checking nAa's updates, so i don't need update notifications on my phone. i always delete this to save extra 2,3 MB of RAM (sorry nAa :))

DSPManager.apk - As stated multiple times across forums, it often drains battery, runs in background, using 3-5 MB, and i can't really see any difference in playing music with/without it. There are better fixes for audio. Search for paul-xxx audio fix for ics.

Email.apk - i dont use pop mail accounts so i always delete this. But if you are using pop mail, there are better alternatives like K-9.

Exchange.apk - Email transport system. If you dont use email.apk it is safe to remove this.

FileManager.apk - I use RootExplorer as alternative.

Galaxy4.apk - This is one of ICS Live wallpapers, and i really doubt that anyone is using them on our phones, remove this! :)

HoloSpiralWallpaper.apk - Another one!

LatinIME.apk - On screen keyboard. You can remove this if you don't use qwerty software keyboard. I found it bit difficult to use it on our small screens, so feel free do delete it if you don't use it.

LiveWallpapers.apk - This really don't need further explanations..

LiveWallpapersPicker.apk - same here...

MagicSmokeWallpapers.apk - again...

NoiseField.apk - this is a bubble Live Wallpaper.

PhaseBeam.apk	- again live wallpaper

PicoTts.apk - Text To Speech, remove it if you don't use it.

QuickSearchBox.apk - Google Search Box that can be placed in homescreens, i really don't use this.

SpeechRecorder.apk

Stk.apk - SIM Tool Kit

Trebuchet.apk - Pretty slow and bloated launcher. If you really want ICS look, use Apex Launcher Instead. But if you want fastest performance and lowest memory usage i recommend LauncherPro which is by far smoothest and fastest launcher out there. Too bad it is bit outdated.

UserDictionaryProvider.apk - Dictionary for word prediction on keyboards. Needeed for LatinIME.apk. Do not remove this if you are using software qwerty keyboard (LatinIme.apk)

VoiceDialer.apk - I don't use this.

VpnDialogs.apk - I don't use vpn

SoundRecorder.apk

There are more apps that can be safely removed, this is just my standard 'setup'. At start, rom was ~108 MB in size, and after removing this apps got to 93 MB.

Eventually I will update this post, with Gapps removable applications and their descriptions.

Feel free to post your feedback.