for what i've seen in hl2 would it be cool in the xfx but i think hl2 isn't good for what i've seen.
xfx is like you said verry good but then they nead to make it totaly divrent, all the codes are made for hl and if they get on hl2, they have to start all over again.
(if possible)the q3a engine or ut/2k3/2k4 is good to but thow's engines are atleast better than hl2.
realy, i vote more for ut2k4 becours of all the posebility's in that engine and the beauty of it and ofcours the poly and the bignes of the level.
realistic ass hell and all 24bit, that's atleast a engine to go for not hl2.