I did use xmonad on OS X a lot, and I liked it. Since I live mostly in terminal emulators and vim, tiling for X11 applications was plenty enough. So, I ran X11

I did use xmonad on OS X a lot, and I liked it. Since I live mostly in terminal emulators and vim, tiling for X11 applications was plenty enough. So, I ran X11 with xmonad fixed to a specific desktop (as OS X allows you to specify that an application should always run on a particular desktop). I used the other desktops for Cocoa applications (without tiling). Unfortunately, Lion switched to Mission Control, and I didn't revive that setup yet. It should be easy to do, since Lion now provides an option to prevent Mission Control to sort desktops by usage.