I've currently been using Ubuntu on my MacBook Pro for just over two months. I installed rEFIt and used to use Ubuntu 7.04 it worked but there were a few problems. But since the 7.10 release I've installed it everything works fine. The sound, lighting, iSight, keyboard lighting, sensors (not sure everything). The only thing that's giving me problems is the nvidia graphic card witch I can't seem to install the official driver. It works until I reboot and then it's set up to the defaults again. But I think that this can be fixed I just have to find some time. Everything else works fine (accept for a kernel bug that doesn't recognize my Nikon camera but that's a another story).
Anyway I thought it would be tougher to setup everything, but now I'm glad I got the a Mac.
Nice day to you.