thanks all four your opinions. I think I'll go for the 8200, since is cheaper and Xmas will probably leave me without much money
A word of warning: the 8200 is a very slow chip. *Very* slow.
My laptop has a 8400, which is visibly sluggy on Compiz when moving or resizing windows or scrolling Firefox for example. Going back to my Ati desktop feels like a breath of fresh air (and that's saying a lot!)
Intel's 4500HD may be slower in 3d, but its desktop experience is better (judging from a friend's laptop).
Ati's 4570 is easily the fastest of the bunch, though. It's not an easy choice, but I think I would go for that, for two reasons: speed and possibility to move to open-source drivers once they gain acceptable power management (maybe in 6, maybe in 12 months, maybe in 18 months - I can live with fglrx in the meantime).
The final sticking point is HD video. Are you planning to watch lots of it? Then you should go with nvidia (but make sure that the chip you choose *can* play HD). AMD is also shaping up in that department, but I think we'll need at least another 6 months before that becomes a viable solution.