http://code.google.com/p/quakexna/Never had time to complete my XNA Quake project due to rl stuff but now the code is available for download to all. This can be a good start for a FPS project. The original Quake level editors work fine for making maps. For the monster it support the Quake format but I think making it work with something like fbx or whatever is a good idea. If you want to contribute to the project and make a fully working Quake let me know.
Enjoy
