I'm no expert but I would guess the board will support any graphics card. The CrossFireX is only applicable if you intend to use two graphics cards at once. I'm not so sure if it applies to the cards that have two graphics cores built in though, for instance would my NVIDIA GeForce 9800 GX2, which has 2 cores work with it even though it uses only one PCI-E socket? My guess is that it would as two PCI-E sockets aren't being used, but it's only my guess.
If you're planning to use two graphics cards then I would guess your best bet would be the ATI route as NVIDIA's SLI doesn't seem to be supported. If you're planning on using one card then either make would, I presume, work. Why not email Gigabyte and ask their opinion?