Cat7? It took them long enough to approve Cat6! Be wary about buying cable. Before Cat6 was approved a lot of manufacturers sold what they called Cat6 cable. Most of it was okay but I think a couple brands didn't quite meet the final spec.
If you do decide to use GigE then make sure you don't untwist too much of the cable at the ends and check the radius of any bends. It really doesn't like it if you bend it too much or untwist the ends much.