My work allowed me to pick any machine and I choose a MacBook Pro. I quite like it especially in that it is built of a unixy kernel (FreeBSD). I also have a personal one as well that is multipurpose for development, and music recording.
A Lenovo re-formatted with a Linux distro is also not a bad choice, a couple other developers in my office opted to go down that route. They opted for Ubuntu.
I have nothing against Linux to be clear, I like the MacBook. For my VPS though, I choose Linux, using CentOS.