This concept by itself is one of those things were I went "Shit, why didn't I think of that..."
OnLive is a service that allows you to play video games remotely, as if they were running on your machine. Imagine using Remote Desktop for gaming, except its a service and the games are all running and the graphics are being rendered on extremely high end servers.
The big deal is "YOU WOULD NEVER HAVE TO UPGRADE HARDWARE EVER AGAIN".
Some of the demo's they had outlined at the presentation is running Crysis on an extremely low end laptop. The service would run on PC's, Macs, and TV's. Imaging having a Mac that can play all PC games. Absolutely incredible. I am so excited its incredible.
They said that the set top box for TV's are so cheap to produce that they can give them away with the service.
Cons: Just one that I can think of, and its that you need a 5 mb connection, which I have anyway, so who cares. I am so down.
http://media.pc.ign.com/articles/965/965599/vids_1.html