7770 is a crap card and is the only card in the 7XXX lineup that is not priced appropriately imo. But I have no issue with the 7970/7950 prices. You want the best, you pay for it, that's how it's always been. The GK104 is not going to dethrone the 7970 so prices will stay that way.
These 7870/7850 price rumours are wrong. There is still a 1.5GB 7950 and a 1.5G 7890 that have to fit beneath the $449 price tag of the 7950 3GB and above the price of the 7870. What are they going to be priced, $425 and $435 ? It's not even worthy of discussing. 7870 will be $299, 7850 $249.
Is the 7890 confirmed? I assume that you're also implying the 7950 1.5gb @ $400, and the 7890 @ $350. The gap between the 7950 and the 7870 may not be big enough to facilitate another card in between the two, especially if the 7870 is 1200 cores at 1ghz, as some of the rumors suggest, which would make the gap about 20% between the 7950 and 7870.
If that is the case, we may see the 7870 at $350, with the 7850 2gb at $300, and the 7850 1gb at $249.
Also, Re: the 7770, I think that it's just priced a little too high, I strongly suspect that it's price will drop to $140 after it's been out for a couple months, which IMO is a very reasonable price for the card. (although performance increases in the $150 range have been small over the last few years, I bought my 4870 in march of '09 for $159, and neither AMD nor Nvidia has put out anything dramatically faster)