is there enough data to be sent through pci express 2.0 to buy into using it?

im building a new computer and everything is a haze on what is the best to get for the money.. i wanted to use sli but then i started to read about express 2.0 and cant find sli ready in 2.0 so would it be legit to use sli or just the 2.0 slot. http://bit.ly/pltLWb