I'm getting the hub 5 with 1gb
I want to connect a PC and a mini box in an upstairs back room, and maybe the same in the upstairs front.
Should I use cat6 or better to plug into the 2.5gb socket on the router? And should I bother with wall sockets or just run the cable directly to the devices?
Will I need a network switch upstairs to split the signal, and if so what kind should I get?
Cat6 or Cat6a Ethernet cable will be fine, anything else is a waste of money. As you are have two devices upstairs you will need to run two cables or one cable and a network switch (about £15) upstairs. I would always advise running two cables, they are cheap, for contingencies. If you use a network switch, you could them always plug in a wireless access point upstairs or a vm pod to give better WiFi up there.