Video Card:Asus GeForce GTX 590 3GB Video Card ($742.16 @ NCIX US) Total: $742.16 (Prices include shipping and discounts when available.) (Generated 2012-02-26 14:44 EST-0500)
It's getting toward the end of the road for both video cards, but you can still find them if you look hard enough. My local Fry's definitely had a few on the shelves when I looked on Friday.
Usually they are harder to find because the next generation cards will replace them with better performance for the same price in the upper end, the 7970 effectively replaced the 6990 as a flagship card even though I believe the 6990 beats it in certain applications.