there was a big argument last year about the 3.0 v 6.0. I believe the consensus was that system dont even saturate the 3.0 bandwidth yet. but I would buy the 6.0 just in case, you never know somebody may come up with a program that does the day after you buy the 3.0.
semp
I sh!@ you not, you can quote that same statement, word for word, with what they were saying years ago about PCI-E graphics cards when they first started to become available when the standard was still AGP8X (well, dual AGP8X, but still, didn't take a year or two for PCI-E to overtake the market).
If they make it, we will come.