I find myself doing development on Windows, Linux, and Mac. Most of the time this involves working on web applications. As such, I was struggling with finding an editor/IDE that would suite my needs on all of the platforms. I may have found it!

http://www.activestate.com/products/komodo_edit/

Komodo Edit. This is a free package that runs great on all of the platforms. The one big drawback in the lack of an integrated SVN client. I use subversion religiously, even on personal projects. For Windows there is the excellent TortiseSVN client that integrates with Explorer but I am still left with working at the command line for Linux and Mac.