Is cat6 cabling really necessary nowadays? I know all advantages of wired vs wireless but most networked devices come with wifi capabilities.
Get ye to a nunnery
Wireless is still tempremental at best in a lot of house, and a shared "medium" - fine if you've only got one or two machines and no major blockages (thick walls, certain types of insulation, water tanks etc), or other devices that might be noisy in the RF bands (cordless phones, video senders, even microwaves).
Unless you can get your wireless router in a very good spot, you're likely to have dead spots, and weak signal areas where the speed will be poor.
Cat6 allows
Per device bandwidth - the switch only transmits data to the device that it's intended for (wireless is more like the old hubs, in that every device gets the data which is less than optimal).
Much higher and more reliable speeds = 100mbit miniimum, more realistically these days (if setting up new) gigabit each way, regardless of how far from the router/switch (within reason).
Can be used with appropriate adaptors to:
Work as phone lines (simple short connector at each end)
USB extender / HDMI With suitable active adaptor (I think you can also get VGA adaptors)
Speakers.
If the house is being rewired anyway, the main disadvantage of Wired networking (running the cabling) is moot, you've got to run other wiring so it makes a lot of sense to put in cat 5e/6 at the same time.
