Tons of USB Thumb Drive Apps

http://pendriveapps.com

http://www.protableapps.com

Update Environment Variables without restarting windows.

All you have to do is broadcast a WM_SETTINGCHANGE after updating you environment vars.

http://ghouston.blogspot.com/2005/08/how-to-create-and-change-environment.html

Do I dare try it?

Microsoft Internet Explorer 8 Beta 1 Avaliable for download.

From LifeHacker: http://lifehacker.com/364289/internet-explorer-8-beta-1-available-for-download

Great .NET decompiler

http://www.codeplex.com/reflectoraddins

Vista Effects in Windows XP

This place has a bunch of utilities to mimic Vista/GNome Effects in Windows XP ('Aero Desktop', Multiple Desktops, '3D Task Flipping'...)
<a href="http://update.docs.kr/entry/Products-Summary-en">http://update.docs.kr/entry/Products-Summary-en</a>