I haven't read many reviews of the 470 but that's what I picked up. It's not any louder than my 260 and only marginally hotter. I expected at least to have a lot more heat coming out of the back of the computer but that's not the case either... it's about the same as the 260.
You do need good a case with good airflow though. The 480 on display (which I'm guessing just naturally runs hotter) at the store isn't in the best case and the fan is at stock speeds and the temperatures reflect what many of the reviews reported: HOT. Then again I think an 8800GT would run pretty darn hot in that environment.
At 55% fan speed the only difference between this card and my 260 is this card is noticeably faster
Ordering my i7 upgrade this weekend. 2nd 470 soon to come