I don't think either ATI or nVidia has a very good handle on how to keep their hardware properly cool. They need to be willing to specify much larger heat sinks and bigger, quieter fans; I'd be more than willing to pay for something like what's on an 8800GTX on any card I bought, even if that added $30 to the purchase price.
Over the long term I have to say I've had vastly better experiences with ATI's stuff. I did just buy my first 2x00-series card, though. I'm already not impressed with its cooling.
Onboard graphics look better and better by comparison.