FYI, you are contradicting yourself.There is nothing wrong with SLI/CF, it's perfectly seamless if you know how to use it. SLI more than CF in this case, because of customizable game profiles.
But you don't need either one for playing at 1920x1080. One GTX 480 will do. And you get customizable profiles (huge in terms of getting the best IQ for different games), physx (bleh), and cuda (yay). Heat and noise are a non-issue. The only negative is power consumption. If it's too rich for your blood get a GTX 470.
If you aren't willing to put up with the power consumption and don't care for the "nvidia package" then just get a 5870. It's a great card there is no question about it. If I were you and was going with ATI I'd actually get a 5970, but you said it's out of your budget.
Higher power consumption generates more heat. The heat becomes an issue as well.
