My friend just bought a new 2.16 GHz MacBook Pro (2006), and it plays Half-Life 2 beautifully in Boot Camp, even at the display's full, 1440x900 native resolution! — He was actually kind of shocked that it responded better than his 3.6 GHz tricked-out desktop gaming PC.
Now, he says that he doesn't need to bring his desktop to college for games! 😄
… There's no HDR rendering support unfortunately, but not a big deal considering how much power's already crammed into this tiny machine! 😃