Hard to say what will be on sale. But generally the "blow out" type deals are on low end stuff. So I'd expect to see ATI 5770's, GT 240's, less expensive stuff like that on sale.
That being said, you can pick up a GTX 460 1GB for $159 after rebate @ NewEgg.com right now. It's an ECS card, but that's pretty dang cheap for a 1GB 460. Think I saw an ATI 6850 as low as $189 right now.
Obviously the 69xx cards will be faster, and therefore more expensive. So the big thing it to decide ultimately what it is you WANT, and then determine the best time to buy it.