I actually got enough RAM to play HL2 without sitting for 20 minutes waiting for the level to load. Now that I did that, the game is more enjoyable, but it's definately a different flavor from Doom 3.
Personally, I like Doom 3's graphics and atmosphere more, and the whole thing seemed very....alive, I guess is the best way to say it.
Half Life 2 is very interesting to look at and walk through, the human detrius scattered throughout the levels is almost suffocating, and very atmospheric. However, the entire game seems quite sterile, all your enemies seem to simply vanish, like they have no background whatever, and they're so nondescript--it's like playing MOHAA: the enemies are everywhere, and they're as easy to kill as baby seals with a machine gun. Doom 3 avoided this problem by having the enemie actually be nondescript hell demons, and have them have interesting movements and are harder to kill.
However, I have to say that Half Life 2 can entertain, but the one thing that absolutely kills the game is the loading. It's retarded in that you literally only load three or four buildings at a time, then have to reload them everytime you advance through the level.
