I still don't really know why folk say the 7970 is over priced. It's a consumer article made by a private company for profitable means. The stark reality is it is better than the 580 by a reasonable margin and can grossly overclock without any hassle to make it vastly superior (to me that means 40-50% faster).
The 3GB AMD card is on par (or cheaper) than the 3GB GTX 580 versions. Likewise the 6970 was priced reasonably high at launch (although the premium to move to the 580 was not proportional to it's superiority). The 7970 requires to be priced higher than the previous best performing single gpu card - that is just reality.
As for the 680, if it has a lower production cost (than the 580 had) then it is not unreasonable to assume it will sell at a competitive price. Many reports mention it is an efficient chip, unlike Fermi. If that is the case, it does not need an exhorbitant price tag. NV marketing knows how to sell (for better or worse, ethically) - It is not unreasonable to suggest they release a superior card and use AMD's high pricing to make consumers double take AMD's prices. "Hey look at those AMD douchebags ripping you off" scenario.
As for people harking on about AMD will just release higher clocked cards to 'hump' the 680, that's an invalid point. IF GK104 is efficient and conservatively clocked, then it may also be an overclocking dream - we dont know yet. My 580 can run at 950 (23% overclock). A 7970 at stock is 925, a lot of reviewers topped out at 1125 (TPU review hit 1075). That's a 21% overclock. Okay, so my 580 is a Lightning but the point is the same, overclocking can be done on both sides.
The 680 will also be the contemporary top tier NV card. It doesn't matter if it is not the uber perfoming card of myth. It is NV's top and possibly the worlds top performing single gpu card. If all the reasonable rumours are true, GK110(112, whatever), the daddy Kepler card IS the be all and end all and NV are in no rush with it. They've seen Tahiti and thought, "oh, is that it!" and focussed on the GK104 launch because they know they can beat it. It's a stern possibility that whatever AMD come up with, Big GK will win. Reasoning?
GCN is AMD's new design. They'll evolve their compute design for better or worse to compete with GK. NV have CUDA well under control. They can shrink it onto the current fab process and make it a monster.
I really think this round of gfx cards are little 'offerings'. AMD saying, "oh looky at our new compute stuff" and NV saying, "oh looky at our new efficient card". I think Q4 2012 will be when the real shit hits the fan and both camps make tweaks and redesigns that establish their proper power play.
Oh, Charlie at S/A says TSMC has halted ALL 28nm processes for now due to an issue.
http://semiaccurate.com/2012/03/07/tsmc-suddenly-halts-28nm-production/
Anyway, all of this is just logical personal opinion. I'm just as eager as all to see the real benchmarks from reviews.