This list is more for me than the masses.

* Application is free.
* Application has a scaled down free version.

Anti Virus AVG Free Edition*
Web Browser Mozilla Firefox*
Desktop Wallpaper Rotator Panorama 32*
Drive Imaging Acronis True Image (Also Norton Ghost)
PDF Reader Adobe Acrobat
Photo Editor Adobe Photoshop
Photo Album Adobe Photoshop Elements
Password Manager AI RoboForm
Blog Editor BlogJet
DVD Backup DVD Shrink*
DVD Player InterVideo WinDVD
Music Player Music Match, iTunes*
Office Productivity Software Microsoft Office, although OpenOffice* is an excellent free alternative.
CD Burner Nero Burning Rom
Media Player Apple Quicktime (comes with iTunes), RealPlayer, Divx Player
Remote Desktop RealVNC*
Hotkey Manager HotkeyControl XP*
File Comparer WinMerge*
Search and Replace InfoRapid Search and Replace*
Music Station Yahoo Messenger/Launchcast*
Find Filename Locate32*
Find Documents Window Desktop Search*
Notepad Notepad++*, Notepad2*
Task Switcher TaskSwitchXP*
Archiver WinZip
Binary File Editor Hex Editor
Little Tools ClipName, SysInternals... Process Explorer, AutoRuns, Junction, FileMon, RegMon, Power Toys... CmdHere, ImageResizer, Open Command Window Here
Explorer Replacement ExploreXP*, Explorer2, Directory Opus
Tivo Tools Tivo Desktop (Because I can't get Tivo HME to work)
Screenshots WinSnap
Launcher Launchy

Developer Tools

DBMS Microsoft Sql Server
IDE Microsoft Visual Studio 6.0, Microsoft Visual Studio .NET
Microsoft DirectX 9.0 SDK*
Color Picker Nattyware Pixie*
Snippet Compiler
Regular Expressions Testing The Regulator*
.NET Class Browser Reflector*
HTML Editor Dreamweaver, 1st Page 2000* which is just like Homesite

Others that I have used and like