I own a PS3 and an Xbox 360. I also own a Gamecube, PS2, PS One, an Original Xbox, 2 Dreamcasts and a 3D0 (I miss Demolition Man). I need another console like I need a hole in the head. But I am going to scrape up some pennies for this one.
I haven't played any games OnLive yet, but I have been taking advantage of the spectator mode. I am the ultimate couch potato because I find myself sitting and watching someone else play Arkham Asylum or Borderlands and enjoying it. If they would get Civilization V to run on it I'd buy in a heartbeat.
It's free to sign up and download the client to spectate and try out demos. There aren't a wide variety of games available, but you can try them out and rent if you're not sold on buying the game. There is also the fact that there is no box. if your internet connection goes down you can't get at your games. Personally, if there is a game OnLive that you like you can't go wrong renting it there instead of waiting for GameFly.