hmm, If I can get Arch to install, I might give it a go. Ubuntu was a bit pants when I tried it for a month early last year (had installed Lion, was pants on the old machine, tried ubuntu before rolling back to SL.) Multitouch gestures for multiple desktops is a must now that I've got used to it...
But I got stuck with it because I had to do ios dev at some point, so I learned to adapt ...
I hear arch and ubuntu both work great out of the box on macbooks.