Well, the game engine is up to you guys, just make sure it's a good one.
As for me, I'll be doing the CG stuff with anyone else that joins, I'm not really into programming, maybe when I'm older and have more time (I know that's a contradiction).
What I'm thinking is massive environments, that are very different from one another (forests, oceans, arctic, something with volcanoes etc).
I don't have any story idea's yet, when I get one, I'll let you guys know, and if this project gets anywhere then almost cool will have to set up a website and forum, and he might have to let CG-Nation know, they have a lot of pro's over there.