Right now the WD 2TB is cheaper than 2x 1TB WD. This is WD though, pricier than Seagate and Samsung. I think going with the other brands you'll get a better price on 2x 1TB, but alas not with WD. The Black Editions are on backorder, but once again no known ETA.
I'm in desparate need of another 1TB drive. Got 150GB left on my 500GB Black and the other 2x 1TB are loaded. Can't find Samsung and can't find WD Black. Had to sell two 1TB Seagates recently when I couldn't fill the request for the Samsungs. Lucky for me they weren't too hassled about the higher price.