Ohh, I found something out about this the other day! I can't remember where mind you.

Like you, I have been a Windows user for years, and have to shut everything down to game.

I found out that the 150ish background processes are just how Linux works, and unless they are active it's fine. Mind you... I can't find the source of that information now, I'm starting to think I may have imagined it :S

Wait, I've found it:
http://talk.maemo.org/showthread.php?t=39760

Chris