AvantBrowser - Tabbed interface for Internet Explorer
http://www.avantbrowser.com/
 
HotBot Desktop - document searcher
http://www.hotbot.com/tools/desktop/
 
Lavasoft Ad-aware - spyware killer
http://www.lavasoftusa.com/software/adaware/
 
Maxthon - tabbed interface for Internet Explorer like AvantBrowser, difficult to decide which is the best!
 
SharpDevelop - opensource IDE for C# & VB.NET
http://www.icsharpcode.net/OpenSource/SD/Default.aspx
 
SmartBarXP - Longhorn-like desktop sidebar
http://www.smartbarxp.com
 
Snippet Compiler - mini-VS.NET
 
Spybot Search & Destroy - spyware killer
http://www.safer-networking.org