My current choice: Larswm. Why? because, while it sits right on top of X, it doesn’t have all the crap that GUIs normally have. There are two separate problems with the current linux desktop GUIs: 1) performance 2) ease of use
1) X sucks at performance. Someone should make a GL-based X replacement. Don’t worry about legacy cards. Anyone using one will still use X for a while, but the future is GL. This would be small, fast as hell becuase of no legacy, and able to do anything apple can do, maybe better.
2) the window manager is not dependent on X for usability except for anti-aliased fonts and nice effects. hey, guess what? larswm is SIMPLE, it is EASY TO LEARN (given some rough edges are gone), and it WORKS. Sure, I would love anti-aliased fonts while browsing or coding, but we don’t need widgets and wadgets to do work: simple is better!
(an ironic note: larswm is closer to ‘modal’ interface of set-top devices than other window mangers, if ya think about it 🙂