Shell/Explorer Tweaks and Tools

AB Commander - Excellent Windows Explorer replacement
ArsClip - Clipboard extender and phrase typing tool
FileBox eXtender - Quick access to favorite and recent folders in file and folder dialogs
Launchy - Start Menu replacement for keyboarders
TouchCursor - Navigation and editing from the keyboard home row

Internet Accessories

BlogLines - Decent online RSS reader
HandyFind - Adds Find As You Type functionality to IE and other apps
Jungle Disk - Inexpensive, secure, reliable automated online backups
RoboForm - One-click navigation+login to password-protected web sites
WordPress - Robust open source blog publishing system

General Purpose

Beyond Compare - Excellent file/folder comparison and synchronization tool
EditPlus - Text, HTML, and code editor
Paint Express - Professional icon, bitmap, and cursor editor
Ultra Recall - PIM to capture, organize and recall all of your electronic information
WinZip - Manage ZIP file archives

Windows/.NET Developer's Toolbox

Dependency Walker - Tells you what DLLs and entry points an application uses
RegSvr.reg - Adds Explorer context menus for [un]registering COM components
Sysinternals - Handy development utilities (Process Explorer, Filemon, Regmon, etc.)
Visual Assist - Add-ins for Visual Studio adding improved intellisense, code templates, more
Visual Build - Automate software builds for Windows developers and build masters

Tips and MS KnowledgeBase Articles

ASP.NET Applications without Web Projects - Alternate method for managing VS.NET web projects
Automating Code Signing of Windows Executables - Tips on setting up application digital signatures
SourceSafe Strategies - Article on promoting/managing projects with SourceSafe
Tame Visual Basic Development With IDL - Eliminate compatibility/reference issues
Team Development with Visual Studio .NET - Microsoft's best practices
Visual Studio 2005 Web Application Projects - Visual Studio 2003-style web projects in Visual Studio 2005
Visual Studio 2005 Web Deployment Projects - Adds functionality to build and deploy ASP.NET 2.0 web sites and applications