360, Wii, DS, PSP, and PS2 (I'm still playing it. Seriously). Bought the 360 myself and everything else was obtained outside of my knowledge or was a gift.
360 is the most played one I guess. I'm tired of shooters and want to get rid of the CoD games that are taking up so much space. I don't know if I want to keep Battlefield 3 or not since it's better than CoD. I'm playing BlazBlue and waiting for Persona 4: Arena. Still have to finish my Assassin's Creed story DLC, Agarest War, and Resonance of Fate so I can start Tales of Vesperia.
Wii exists only for when friends come over so we can play Smash Bros or Mario Kart. Beat Metroid Prime 3 twice, Okami twice, and have to start Skyward Sword (see 360 backlist).
DS is for the Devil Survivor games and Strange Journey. I want to pick up Etrian Odyssey and Castlevania Order of Ecclesia and start Kingdom Hearts 358/2.
PSP is for Birth By Sleep and Persona.
PS2 is currently running Persona 4. Gotta play P3, Nocturne, Digital Devil Saga series, Devil Summoner series, Ico, and Shadow of the Colossus.
A Vita is on the "maybe eventually" list. Persona 4 Golden! Chances are my brother's gonna buy it himself like he did with the PSP. 3DS I might have bought if Megaman Legends was coming. Kingdom Hearts may or may not get me.