if you are playing star craft 2, or competitive FPS the faster CPU + slower VGA (but with lowered graphics settings) might give you the best experience....
for this money, can't you get a cheaper i5 (2310, 2400) and a 1GB 7850?
I agree. As good as the i3 is, an intel quad is better in a few games now and is much more future proof.
As far as the A10 suggested above, I would not go that way. Seems pointless to buy an APU with a mediocre cpu part and then add a discrete card. If you wanted to go AMD, an FX4100 can be cheap if you live near a microcenter, or wait for Piledriver which should be out very soon.
But the sweet spot for gaming now IMO is an intel i5, and you should be able to fit that into your budget. If not I would even try to save a bit longer or delay a game or two in order to get the i5. I would think that anyone into pc gaming would spend at least a few hundred dollars a year on games, so what is another 50.00 for the processor?
Edit: As far as upgradability, the AMD might be more "upgradable", but for games, intel is far superior at the present, and with the state of AMD, who knows what will happen to Steamroller, and even if it comes out on time, still might not be better than an i5, especially in gaming. Plus, if you are budget constrained, why would you want to purchase a new CPU in a year or two?