While I agree that it's nice to have native (assuming it's actually native) ports, HL2 and most of the other Source engine games have reportedly run great via Wine for a while now: http://appdb.winehq.org/objectManager.php?sClass=application...
I fiddle with messy integration issues on embedded Linux and Android professionally, and am about as qualified as anyone could be to make that work. I never once bothered trying to get wine running. I installed Portal last week without a moment's thought.