You could save a few bucks by getting a lesser clocked i5 and H77. If you really are going to run SLI in the future you will need a z77 that supports SLI. However, do you really think you are going to run a 2nd card? Typically people that run SLI get both cards at the same card. If you are thinking down the road you are usually better off selling your card and getting the new gen card. Unless you get another gtx670 at a cheap price that makes it attractive.
I personally think your system is fine the way it is. I'd save your pennies and wait for the next gen Intels to come out and get that. Haswell is supposed to be a good leap in performance over the ivy bridge.