Re: Upgrade time. GTX285 to...?
If a 480 is too much power and heat than a pair of 460's in SLI will be too much power and heat as well. Also WoW's SLI scaling is pretty horrible, and since that's the game you play the most a single 480 would perform better as well.
If you are dead set against a 480 and don't want a 5870 I would just wait until after the expansion to get a new card. If they don't fix the SLI issues with WoW and you buy 460's in SLI you are going to be stuck with the same performance you have now or worse due to the DX11 hit.