Green Graphics Adapter Recommendation

[Bob - BLU]

I have a Linux server that needs a graphics adapter.  It will spend most of it's time displaying an X login window, and the rest of the time displaying an X session while maintenance occurs.  No games here.  But I expect to be running a few virtual machines under VirtualBox or VMWare.  So I'm looking for a graphics adapter than can handle that (most any), and not chew up much power as it spends its life displaying the login window.

The motherboard has a PCI 2.0 x16 slot for an adapter.  I was thinking an NVidia based card as they seem to have the best drivers (proprietary is acceptable here).

Any recommendations for a 'green' card?