Cat7 is mostly pointless. http://en.wikipedia.org/wiki/Category_7_cable#Class_F_cable
There are different classes of it, but even Cat6 supports 10gbps which translates to about 1250 Mega Bytes per second!
CAT5 supports up to roughly 125Mega Bytes per second but in reality in a home environment it would be nearly impossible to find hardware to talk to each other that fast.
I have a good gbps router and bought a new "My Cloud" device from Western Digital which is very fast compared to most network devices and I get a max Read of about 80MB/second.
The BOTTLENECK is always the slowest component whether it's the Router, PC or other media device.
So CAT5 is more than enough for most people but if you're concerned at all for "future proofing" especially if it's a hassle to install then just get quality CAT6 Ethernet cabling.