Honestly, if ATI Tool was coded to control NVidia card dynamic fan speeds tied to temps like it can for ATI cards, it would be perfect. I just upgraded to a 7900GT from an X800XL and that is my biggest regret (even more that the slight hit in IQ). I loved ATI Tool.
Nothing was as simple to set up and as useful. My perception of RivaTuner is of a big russian bear that's clumsy and hard to configure but in the end gets the job done. ATI Tool is the quick, efficient counterpart that does all the really important stuff (temp monitoring, fan control, overclocking/voltage, and discreet temp display in the systray (without any polling issues that slow games down), but it only works completely for ATI cards.
