If you already have a 360, you already have access to most of the worthwhile PS3 library. Wii makes for a better complimentary system imo... though your specific taste in games may mean a PS3 might be better, given you seem to favor western stuff (fps, wrpg, sandbox, etc) which Wii is kinda lacking in.
Personally, I'd say skip both and get a 3DS. It'll have more exclusives than PS3 & Wii combined over it's lifetime probably.







