Zalman will release their new VF-1000 cooler, supporting G80, it's supposed to come out by the end of this month, or early next month, according to my local store, and a few web-site previews I've read. That cooler looks absolutely beautiful, and as always, will be very silent (that's Zalman's trademark, silence without the loss of efficiency).
I got a VF-700 ALCu for my X1800XL (which isn't installed anymore since I got myself a GTS, but it's still in its original box), and it was barely audible at 100% fan speed, and it maintained my XL at 43ºC to 45ºC idle (depending on the room's ambient temperature), and it never ever exceeded 64ºC full load during a hot summer day (according to my personal logs), and all that while it was over-clocked.
Granted, the GTS is a more voracious beast than the X1800XL, so by default it already consumes more power, and generates more heat as well, however I'm confident that the Zalman VF-1000's efficiency for any of the G80's around will be as good as my VF-700 was for my ATi card. I can't wait for it.