For sure. I don't think the x8 PCI-E lane will bottleneck too much. Definitely do it! GTX260 in SLI is a beast of a setup!
Originally Posted by c00lkatz
It's not the size of the screen, it's the resolution, though the larger the screen, generally the higher the resolution. At a higher resolution, yes it will help dramatically when you start cranking up the eye candy. I would get a bigger monitor with a higher resolution now, since your GTX260 can handle it very well, and then SLI later on down the road.