The ATI radeon 9600, 9700 and 9800 Pro series do a remarkable job with dual monitor displays. They also enable you to set multipule color profiles and do some very fine tuning on the monitor calibration side of things.
The other advantage they have over the Nvida Gforce series (even the newest ones) is that they have more power and seem to offer better stability. I have the 9800 Pro and I'd swap my granny before I'd give up this card.
Ultimately, it will come down to a matter of preference. As Chris H said, "check the specs."
** Paris **