http://download.cnet.com/windows/?tag=hdr;snav CNET's download site is filled with both free and not-so free software. Most of the software that requires a purchase has a try before you buy option. CNET also has a great search option if you're looking for something specific.
I use GIMP (GNU Image Manipulation Program) and Spybot - Search & Destroy here at the house, the GIMP interface has a lot going on, but it's pretty useful tool if you don't already have another photo editing tool. Spybot is a free antispyware tool that works really well.
BTW, I can't speak for the rest but GIMP and Spybot are not restricted to Win 7, they work great in everything from XP to 7.