Freewheeler, if you have a very good, top of the line PC, it might be a good idea to get it for PC because the game itself will be cheaper and a really good PC will get you even better graphics than the Xbox.
Myself, I play it on the Xbox. I prefer the more relaxed feel of using the controller while sitting on my bed. Also, I don't have to worry about whether the game will run well on my system or anything like that. I know I can just go out and buy it and it will play just as it was intended to play. The downsides of Xbox are: you can't use mods to alter anything about the game and the Xbox game is about €15 more expensive. Graphically, it looks better than it ever could on my PC but perhaps not as good as it could on a really good PC (but to be honest, I don't really see the difference between Xbox games and PC games that much as I care more for beautiful design choices than for technical prowess).
