I caved and bought a Mac Mini 2ghz a couple of days back. I quite like OS X and it has quite a good out of box experience. My only complaint so far is that arty farty aluminium keyboard and the one button mighty mouse. For a developer they both suck in terms of usability and ergonomics. I ended up buying an older A1048 wireless keyboard with proper keys and a proper two button Logitech LX6 mouse to replace them both.
Anyway it's been a long time since I got quite so excited about a new computer. I'm looking forward to honing my Python and Ruby skills in an environment that doesn't have my usual MS crutches like VS.