I hear alot about these consoles breaking down, but I must say that in the years I have had my xbox, practically since it first came out, I have never had mine break down, even in the heat of the british summer, playing all day, non-stop, only sometimes will it overheat, but if you switch it off at the first signs of failing (melting graphics and freezing) you should be fine.
Now, compared to a computer running a game at full spec, the graphics on the xbox are not all that great, even in HD, but are still acceptable for anyone who is not a video/audiophile. I can't compare to the PS3.. because I never bought one.
Now to xbox live... tread carefully here, this service provided by microsoft is... alright, if you can handle premature kids screaming down the microphone, and if you feel like paying upto £4.99 a month for this (rather lacking) service, it's alright, you can sit and play games with your friends in an xbox live party all day long if you have the time.
Another snag of xbox live is the downloadable content, games companies like bungie produce things like map packs after the games release, then charge 800 microsoft points for them and won't let you play your favourite halo 3 playlist until your fork out the cash... low brow if you ask me.
Also with all this expesive downloadable content, you will need a much bigger hard drive than 20gb, upto 300gb if you plan on copying your games over to the hd and buying others over xbox live.
Xbox Live 2/5
Fun value 4/5