I don't think you'll be needing three-way SLI
Three way SLI doesnt mean a whole lot more than that it has three PCIe 8/16 slots available. Its become pretty standard to have multiple PCIe slots on mobos these days anyhow. More than a single PCIe slot is a very nice feature seeing as it allows you to toss in a multitude of new goodies from USB expansions to SSDs to of course, GPUs. The term three way SLI is more of a marketing term than much else as I see it. A very nice feature providing you dont pay too much for it, and heck, can even save you a good chunk of money in some cases.