[Mac OS X] VoodooPad
VoodooPad is perhaps one of the coolest things I've seen for a while. It's a lovely, pure Cocoa native application... that is a personalized wiki specifically for note-taking and brainstorming.
I've been using StickyBrain for my random note taking and organization, but I'm wiki-mental enough that I might switch to VoodooPad.
That is all.