Quick post: I just discovered this kick-ass Window Services FAQ. I just went through the started services on Windows 2000 and stopped everything I wasn't using - but double checked the list first. My computer now uses less memory and cutting out all the NetBios and Remote Registry crap made it much more secure.
Speaking of secure - I'm now also running Tiny Personal Firewall and it rocks. I had to bring my laptop into work the past few days and the network (like many big corps) is like a virus-laden sesspool. Really basic, but it works perfectly. A definite for those of you still running Windows.