I vote physics, something that is really going to change the way we all perceive games from now on, and I am damn glad about that. :P
Edit: Yes, I know Source™ isn't the first engine with physics, but the way HL2 is going to use them is nothing short of amazing, atleast in the multiplayer...
o.O thats odd alot of people i know say it works fine but, heres a new image link :P
http://img13.exs.cx/img13/6724/cs-s.jpg
http://img16.exs.cx/img16/8240/cs-s4.jpg
http://img16.exs.cx/img16/9647/cs-s3.jpg
(dunno if this has been posted)
Just to let you guys know theres a better looking version that has been released, heres a comparision: http://members.cox.net/neog/cs-s.jpg
The link: http://www.csbanana.com/dl/dl.php?1257
Or just mabye..........he doesn't wear a HEV for the first part of the game and then alyx gives it to him and then.....I need slee-*head slams onto keybaord*....zzzzz..zzzz.......zzz....