The main advantage of Cat 6 over Cat5e is for PoE devices and even then it's negligible. In almost any residential or light commercial environment its very unlikely that you would be running anything more than a 1Gbs switch. Cameras are all 100Mbs. Cat5e has always been able to handle 1Gbs connections, same as Cat 6. Cat 6 is 23ga copper, vs Cat5e 24ga. You can now find Cat5e in 22ga, specifically for dealing with high power PoE devices.
It's very rare to transmit AV signals, what all these streaming devices are doing is receiving IP Ethernet signals and transcoding it to h.264 or some other video/audio format at the device. The Cat6A, usually shielded in this case, comes in when you are transmitting that raw h.264 or MPEG signal. Cat6A is the standard for 10G networking and although Cat 6 can work for it too in some circumstances, the 6A is designed to take into account alien cross-talk. Because in networking environments, you will have large bundles of cable running together for long distances, the potential for interference between cables becomes greater, 6A is designed to help minimize that.
In the spirit of GJ, go ahead and run 6A shielded, because if you're going to do something, might as well over do it, then over do that. If you're dealing with a home/workshop/small business that actually would need it, then chances are you're not looking to save a buck on a cheap roll of cable or which jack to use...
