I always do all that.
Here's what I usually do when preparing to launch my game:
-- Turn off my messenger services (MSN & AIM)
-- Shut down my email
-- Unplug my ethernet cable
-- Get rid of as many system tray icons I can (I don't know if that makes a difference, but I do it anyway)
-- Shut off my Winamp/Windows Media Player
I downloaded a program to track how much of my RAM was being used -- and even *after* doing all of the above, I'm still apparently using almost half of my RAM. I can't help but think that there must be something else I can do. Would defragging the hard drive help? I don't think there are any programs I can uninstall -- I've already uninstalled all of the ones that I don't use, and it doesn't seem to be helping a whole lot.
As an aside...does the amount of available hard drive space affect things? I have a 80GB harddrive, and I always try to keep *at least* half of it free. Shouldn't that be enough?