We covered this some time ago, but the ATI Radeon X1950 XTX is now official. ATI's new flagship PCI Express graphics card will cost you $449, which is pretty cheap. It's based around a 648MHz graphics chip and 1GB of fast GDDR4 memory running at 2GHz. There's also a new heatsink design to cool the graphics chip without sounding like a runaway lawnmower. HardOCP have already tested the card and found it to be pretty speedy and pretty quiet, delivering good prefomance for the price. The new card will be available on September 14th.
UPDATE: Actually , it only has 512MB of GDDR4 RAM: I was getting my Ghz and GBs mixed up...
ATI Radeon X1950 [ATI]