Well, I thought of this a long time ago but I think it isn't something thats impossible to do. Why don't we all just get together and work on our own fps similar to halo, I am sure we have the mappers and modelers and textures. I am a coder myself, we would need some more but I am sure there are some here. I don't know if its a great idea, personally I hate halo2 for pc with a passion, not because its for windows vista but because it looks worser then halo 1. If you like the idea or just want to give some input feel free. You can pm your details and what you want to do if you feel like helping

Basic Todo(WIP)
Get a good team ( doesn't need to be huge but just enough of everything)
Find a engine to use for this project(I have a few ones)
Change the Name of our game (I made it up in two secs)