Alright, so here is the thing. If you get a Z77 mobo and stick a Sandybridge CPU in it, basically it will function exactly the same as if it were a Z68 board. All of the features and abilities are there and you can use them, but you will not be able to use the features added with Ivy Bridge.
If you do plan to get an Ivy Bridge processor in the future, absolutely get a Z77 board so that when you do upgrade your processor you wont need to upgrade your mobo as well just to make full use of the chip.
should i get the z77 mobo i linked is that good for oc?