Don....Don't do this to yourself and become a video game system monogamous type person because you will miss out on a lot of games trust me. I own all of them 360, PS3 and Wii and I play them all when I have time and here are some of the jewels that each have
360: Mass Effect 1 & 2, Fable 2, Gears of War 1 & 2 and of course Halo
PS3: Metal Gear Solid 4, Demon's Souls, God of War 3, Folklore, Valkyria Chronicles.
Wii: Wii Sports resort, Monster Hunter, Super Mario Bros Wii. Mario Galaxy.
I love variety so I have to have them all but put it like this: Like shooters? Go 360 Like RPG's and actions type (with amazing graphics!) go PS3, Have a lot of friends and like swinging at stuff and play fake bowling and baseball go wii.
Hope this helps =)