Thunderbolt's only nice feature is you can daisy chain in series and it may provide enough power so you only need the cable. Otherwise, for hard drives, you would need RAID 0 with 6 drives on the fastest performing drive before you could claim you're using it for bandwidth. It's just too bad USB3.0 doesn't supply enough juice (4.5W at the most)... I can't wait for the USB spec to come out that can provide 100W (25W would be good enough for pretty much 99% of peripherals)
100W has been possible (though AFAIK never implemented) since USB 2.0 came out... My motherboard currently supports 10-12W on all USB ports including the 4 USB 3.0 ports, http://www.gigabyte.com/microsite/185/on-off-charge.htm
& up to 30W on up to 3 ports (10W each) when shut down thanks to the 6 amps my PSU supplies over the +5Vsb rail.
From the official USB specifications:
The USB 2.0 PD Standard-B connector is defined to facilitate deliver of up to 100 Watts. An ID pin supports PD identification. Refer to Section 3.2.5 for mechanical details, pin assignments, and descriptions.
The USB 3.0 PD Standard-B connector is defined to facilitate delivery of up to 100 Watts. An ID pin supports PD identification. Refer to Section 3.2.6 for mechanical details, pin assignments, and descriptions.