I don't think the 480 Ultra card with the 512 shaders will be launched before 1-2 months when the B1 revision would make it feasible. I have heard $380 and $530 for the 470 and 480 respectively.

For the 470, it's a better card than 5850 and is slightly slower overall than the 5870. But it has some advantages like CUDA, PhysX and probably very superior tessellation performance. So I think, if 5870 stays at $400 and a 470 can really be bought for $370, the 470 will be the best choice among the 5850-5870-470 options.

However the 480 seems to be more of a mixed bag. A 15% increase performance for a 30% increase in price is not unheard of - when you reach the top, you pay much more for every little extra you can get. However this doesn't make it a better choice. If rumors are to be believed, the performance / price of cards are as follows:

5850 - 85x Perf / $300 : 0.280
GTX 470 - 95x Perf / $370 : 0.255
5870 - 100x Perf / $400 : 0.25
GTX 480 - 115x Perf / $529 : 0.22
5970 - 140x Perf / $700 : 0.20

So price / performance is really in line with ATI offerings, and it goes down as the price increases. Nothing unexpected and nothing new.