I think we can expect Killzone 2 to be better game than the first one, since it probably is pretty high on Sony's priority list, and PS3 fares much better against 360 than PS2 against Xbox evening things up even further. Killzone 1 was a mediocre game, but I'm willing to give that dev team another change to prove themselves. They clearly have talent KZ1 could have been pretty good with small tweaks. and With PS3 it's quite possible that they make the jump from mediocre to good or even better. The hardware helps there a lot and it seems they are working on it pretty long time making sure that this time it deliveres...(not as good as that video of course, but still.)
I think it's definately something Playstation owners can look forward to, especially since there haven't been that many good fps-games on Sony platforms. Resistance sure looks like a good game, but there is room for more than one I think.