Hoo boy... Can o' worms comin' through!!
These are the ones I use either constantly or on a regular basis...
PowerPro- For oh, so many wonderful reasons.
xplorer^2- Man, what a concept... Two file panes=more work done. Who'd a thunk it?
JS Pager- Since discovering the concept of Virtual Desktops in Linux, I can't live without it.
FireFox- Sorry Opera lovers, it just rubs me wrong. Don't try to convert me, I've made up my mind.
Avira Personal- Not.One.Virus.Ever.
7-Zip- Obvious.
GNU Utilities for Windows- NOT the Cygwin ones!! (ech!)
AutoHotkey or
AutoIt- Your choice, they're both good.
Scite- For editing my Auto-whatsit scripts.
PDFCreator and
PDFTK and
PDFBlender- Cause I'm too cheap for Acrobat Distiller...
XnView or
IrfanView- Take your pick.
ContextEdit- h@x0r those pesky context menus! (linked from a google search because PCMag wants money for a freeware product...)
And I probably missed a few...