Internet

MiniAIM

Microscopic AIM client. Perfect for carrying around on a flash drive or floppy disk.

http://miniaim.net/

3D modeling

Google SketchUp

A really easy to use program designed for quickly making blocky 3D models of buildings.

http://sketchup.google.com/

Utilities

allSnap

allSnap is a small system tray app that makes all top level windows automatically align like they do in programs such as Winamp or Photoshop.

http://www.cs.utoronto.ca/~iheckman/allsnap/

Launchy

A neat little tool for quickly launching programs. Hit Alt+Space and just start typing the name of the app you want to start.

http://www.launchy.net/

Lclock

Fixes the rather horrid default taskbar clock. Allows a pop-up calandar on click, skinning, changing & hiding the Start button, launching the Start menu from the clock and more.

http://www.neowin.net/forum/index.php?showtopic=157465