Witcher 3 is getting bundled with current gen cards to prevent people waiting, though personally I'd WAIT for a price drop and patches. You just know that they'll do a lot of fixes on this game over the period of a year if you know the history of W1 and W2.
I'm right at the point where I'm starting to recommend a 3GB video card for future proofing. I think DX12 (or Mantle) and the influence of next-gen consoles will soon cause a jump in the amount of VRAM recommeneded.
There are other reasons that suggest 2GB may still be fine for several years (streaming from System to VRAM) but since no one is certain I'm recommending people with about $300 wait for a GTX860 3GB card or better.
(Currently I recommend the GTX770 2GB, or R9-280X 3GB...