Learned more about GtkTreeView trying to fix the rating system in Rhythmbox. In general it's an amazingly powerful and extensible implementation (kudos to kris et al), but I'd be glad if some GTK hacker pretends to fix things like the ability to render widgets inside it or the lack (IMHO) of fine grain control over the individual cells.

And seeing some of you are talking about LISP recently...

I'm learning LISP for the AI classes in the university, and I use CLISP, which I find ok but not really great. Which one is in your opinion the best LISP development environment for GNU/Linux in particular and UNIX in general?