Which 580 should I get?

[Winger]

680 all the way. Believe me the 680 ROCKS!

Memory above 1,5 GB does only matter at higher than 1920x1200 resolutions. If you dont drive higher res dont bother about the ram.
As for the power consumption the 680 is much more efficient than the previous generations since it automatically clocks down and drives power down if in 2D or idle mode.

Winger

[Dr str@nglove]

i have this one http://www.hardwarecanucks.com/forum/hardware-canucks-reviews/43487-gigabyte-gtx-580-super-overclock-review.html

[Jatta Raso]

Originally Posted by Winger

As for the power consumption the 680 is much more efficient than the previous generations since it automatically clocks down and drives power down if in 2D or idle mode.

Winger

actually video boards have been doing that for some time now; my 570 does just that and i don't think it's the first ever..