A new cross-platform text editor. Though it is still in alpha with a few inevitable rough edges, this seems to have a lot going for it. In many ways, it combines the best features of Vim with those of Textmate. The 'Goto Anything' feature, and the way selections are handled are particularly nice. I'm on a Vim jag at moment, but I'll be watching this with interest.

Detailed article about Vim on MacOS X, with some great tips about the most useful plugins and settings.