Well if you want to base your opinions off of onw diagram, there are plenty of benchmarks in games were the 5970 isn't that much better, I am not saying the 480 does better in performance, but I would say its right up there with it.
Then the 470 beats the crap out of the 5850 in everything period, and then gets higher FPS's in pretty much every games benchmarks, I am not writing this out of my azz, yeah there is certain if ands, and, buts, but in general I wouldn't place the 5970 as the route to go when buying a card, for many reasons. Also with that stated if I wasn't getting it why would I get 5870 when for $350, I could get a GTX 470 and with out OCing it get just as good fps in 1920x1200 then the 5870, not to mention I could get the asus 5850 and oc also and it would perfrom just as good as the 5870.
Plus if you want to talk about heat and wattage, I am not sticking them in my stock dell computer from k mart, so that isn't even a problem in my case.
And since your not satisfied with the "small" gain in fps, I would consider that your not interested in 3D or PsyX, which is what nvidia is offering a complete package, that actually works out of the box, how long has it taken them to get the newest driver out to get things the work, there lucky they did cause that would take that "small" increase a lot higher.
Obviously if your all ATI then nothing Nvidia has to offer will be good enough for you even if it did spank the 5970. The ATI cards were the best around cause there was nothing around, and I just hope ATI fans aren't scared of a "little" competition.
Intel is on top of AMD-fact, Nvidia is on top of ATI-fact. Intel with Nvidia on top of AMD with ATI-fact.