I had only owned an Xbox for 3 days before I got this (far better graphics than my old PS2 by the way).You simply put the disc in, connect it to the broadband wireless router (Netgear Router off Amazon, 5M cable off Ebay for £1) and in less than 5 minutes, you are all set up and online.
I was gobsmacked how good it is being able to chat to anybody in the world as clear as if you are on the phone.
The games I have tried so far are Forza Motorsport (brilliant), Project Gotham Racing 2 (came with the Live kit and also brilliant), Halo 2 and Area 51.
Any Xbox owner must get one of these if you have broadband!