How-To Geek has a nice writeup on how to create a shortcut or hotkey for the “Safely Remove Hardware” dialog. Comes in handy if you’re like me and use a flash drive alot.
Lifehacker has a great writeup on running Windows apps inside Linux with VirtualBox.
MaximumPC HOWTO on tweaking XP, from speeding up the Windows Start Menu (to give the appearance of a boost!), to diagnostics, and other enhancements.
CodecInstaller helps determine what codecs you need to play a media file properly. If you end up using the software alot, drop the guy a couple of bucks, since the app is free.
From Lifehacker, disable the “Need your permission to continue” prompt
Lifehacker has an article on how to reclaim memory by managing running processes. Not for your average user.
A nice article in Wired:HowTo wiki on how to optimize your fresh Ubuntu installation with a few add-ons