Future protection is what I see it as however. With SLI you just buy one card, and when you need a second, plonk one in, plus, they will be much cheaper later on.
Thats why I'm so stoked about SLI, and these new cards. Now that they come in 512 per card, I will/would buy only one, and as I said, if and when I need a second, grab that second.
Yan Booth