The thing is that the 480 is performance-wise between the 5870 and 5970 and priced accordingly. What would really make the 480 pay off for early adopters would be devs picking up on massive amounts of tessellation, where the ATI cards fall flat. The 470 is definitely more bang per buck, but doesn't have the same performance as the 480 in GPU-intense situations.
Personally, I'm going to be picking up a 480. The slight boost over the 5870 is really just a bonus IMO. The real reason I've been bearing towards nVidia for the most part is the extra features: CUDA, better compute architecture, PhysX (however rare, can't stand having options I can't enable), 32xAA with little performance impact is pretty sweet too.
And about the heat/power "issues": if you are even considering a 5870 or GTX 480, you're likely to have above a 600W PSU. They're enthusiast level cards for a reason, don't expect them to sip gas. It's not like running either of them will suddenly add 40 bucks to your bill. And as for the heat, the 295 got roughly that hot, and I've seen friends with 4870x2s that have had 90C and up under load. High performing parts get hot, what a shocker.
The only real issues here, in my opinion, is whether or not the slight performance increase and other features are worth the ~$80 more for the 480. For many, there are other things they could spend the $80 on that are needed more. Personally, I'll spend it on the 480, simply because with an nVidia chipset mobo, I'd not be able to do Crossfire with an ATI card whenever I wanted to, which sucks. I'm also kind of intrigued with the numbers in SLI scaling that the 480's been getting. Once I up my PSU from a 850W to a 1.2KW, and move on to the i7 or next gen CPU, I might pick up a second one.
Both companies have good products though. I see this as only being good for gamers, as each company will keep trying to push out higher and higher performing parts, giving us better and better hardware to play with. Whether you're green or red, PC gaming is far from dead!