I have a macbook. It's solid but I'd avoid it for linux (which I've decided I prefer to osx) - the single-button trackpad alone makes it a bad choice for linux. If I were getting a new laptop now I'd get a high-end thinkpad with lots of RAM so I could use vmware effectively. I have a friend who has just done this and raves about it - he runs Ubuntu.

Some people can get X11 configured to do wacky things with the keyboard so you can run linux. I figure - why bother?