Unless you have a monitor with a resolution I have yet to see (3840*2400 or something) 2gb will provide you with next to nothing. Though I have not seen any reviews on the 2gig 285 yet.. the reviews on the 2gig 4870 show a loss in some games, a gain in others of -1% to 1%... IMO not worth the cost, money is better spent on an improved cooler to get higher clocks on memory and core.
Perhaps the 285 can make better use of 2gig, but i doubt it would make a difference beyond what an overclock can give you, probalby not even close.. Besides that, regardless of whether 2gig is worth it or not we will see 2gig 4890's at some point so we can complain anew again...
1 gig is a massive improvement over 512 at native 24", 2gig over 1gig is not. At native 30" we start to see a small difference in a couple games.. but not much of one, and the highly over clocked cards keep up and surpase, for the same price.. Granted though, when we do start seeing resolutions in the 3000ish range 2gig will be a must... but why would I plan a purchase around something that wont happen until my card is far beyond obsolete?
Must we compare a 285 toa 4890 every day? Yes, the 285 is better and that is not goign to change. There is no point comparing an OC card to a stock card, except in a price/performance comparison. Obvisouly the 285 overclocks too...