360 for the low cost probably makes more sense for a next-gen newbie. PS3 is more of a purchase for the long game - it's usually only after a year or two that Sony machines start to come into their own as developers figure out how to code games for them (360 being more of a low/mid-range PC in its machine-gizzards), plus firmware is updated every so often with new video codecs for MP3 playback, so it's probably worth not getting a PS3 until this has happened a few more times and the machine's a bit more impressive. The shop should have a lot more stuff you can download by then, too.
360 has had a head start on PS3, and thus has a few exclusives, a decent-sized second-hand catalogue, and the chances of getting GTA4 are quite good, as they pressed 3 times as many copies for the 360 as they did for the PS3, and my local gaming emporium has yet to sell out of 360 copies. Even if you do get ring of death, they fix the machine and send it back to you quite quickly, and it probably won't happen for months anyway. You might even find a 360 second-hand that's already been fixed if you look around.
