Personally, only a PS3 and PSP.
My brother has a DS that he barely uses, so I use that whenever I want to play Advance Wars.
My sisters have a Wii that I play occasionaly with friends. I even chipped in $50 for it, because I wanted to have some share of it when Smash Bros. came out. So I guess I kind of own it.
Anyway, I play PC/PS3 during daytime, and every night in bed I play on PSP.