Free software I've been happy with
MediaMonkey - A while back I mentioned I was searching for a new music player, something that would let me shuffle through my library nicely. I tried nearly everything out there and 95% of it was awful. Media Monkey is awesome. Less bloated than iTunes, more feature-rich than Winamp, MediaMonkey has it all. I went from being bored with my massive music library to being entertained again.
RocketDock - This is a sexy lightweight little program launcher. I always used the built-in sidebars in XP but this is sexier.
Notepad++ - My favorite programming editor. I keep finding new features in it that make my life easier.
Pidgin - I replaced Trillian with this after being horrified by how bulky Trillian Astra looks. I still like the simplicity of Google Talk but this is cool for all the other protocols.