Taking money out of the equation, a PC is best for FPS gaming, and FPS gaming only, imo. The problem is, you really have to keep up on your graphics card and processor every couple of years to play the latest and geratest PC games. A pretty decent graphics card alone will easily run you more than the $300 for the premium 360.
The 360 and PS3 will be THE console systems for the next 10 years (at least) imo. The Wii, although interesting, is not a HD system and I think that is a major flaw by Nintendo. Hooking that up to a big screen HDTV will render it blocky and very "gamey" looking, whereas the PS3 and 360 will look gorgeous on the big screen, especially when compared to their eirlier PS2 and Xbox models on the same screen.
Definitetly pay the extra 100 to get the premium system if you choose 360, you get $190 worth of stuff for $100, pretty good deal.