Well i cringe to say i'd go with the mac (if i were you, i'd never get one) if you like macs. They are well known to be much better for Multimedia. Plus the 2gb ram and the extra 128 (i know this vid card is VERY nice) would be REALLY nice. Also is price a factor? Which one is cheaper?
Another thing is I noticed that you said this is urgent. Am i to understand you're rushing into buying a computer!? I would HIGLY reccomend not doing that. Take you're time ask people on other sites, ask you're comp friends, or even you're local (has to be trustworthy too) computer salesman.
BTW this is just my 2 cents. Don't put all you're trust in someone you've never met.
"When you are born, you have a resposiblilty to program you're own mind, if you do not accept this responsiblilty, then the world will do it for you"
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