a good notepad replacement
Freecommander or similar for file organising
Irfanview for fast texture viewing / conversion
Paint-Net for texturing
PhiBuilder for Rigging
Winamp for Sanity
Winrar for archiving Files
Sketchup (plus Ruby's) for model creation
Roadkill for UVmapping
UVmapper for UVmapping

and various hardware addons I use like a N52te Gamepad, M$ Ergo Keyboard with a programmable bank of buttons etc...