I just stumbled upon a great new service: GameFly. It is a service that lets you rent as many video games as you want for about $20 a month. It works like NetFlix: You get two out at a time and receive them by mail. When you are done, you send it back (in a free mailer) and get the next one in your queue. You can keep it out as long as you want.
They have tons of games titles (3000+ by the latest count) and in multiple formats: XBox (360 too), PS2, Gamecube.
Why buy, when you can rent? Go ahead and check it out: