Scott Hanselman has the 2005 Ultimate Developer and Power Users Tool List, which is worth a look.
I’ve been using a few of the tools on the list… Notepad2 is a brilliant replacement to Notepad, though it falls over when working with large files (as Jeff Atwood points out in Notepad strikes back).
There’s a whole stack of useful tools over at SysInternals. Like Scott, I also love ProcExp which is a great help with removing spyware which AdAware and Spybot can’t remove.
Check out the full list on Scott’s blog!