Definitely go for the 650TX V2, its cheaper, more efficient, and just as good overall. No reason to pick the 650TX which is being phased out, the V2 is a much better pick at current pricing.
Will the 650TX V2 be sufficient for some of the newer video cards? Or would I have to buy a new PSU down the road, once I upgrade to a newer video card?
My current video card still works great after 2 1/2 years, but eventually it will get replaced. I intend to stick with my EVGA 9800GTX+ as long as possible, which means until a game comes out that it can't handle, or it fails on me.