those usb hubs are really going to be the biggest drain. i had to pull mine out because it was pulling too much power from my dsatx and not allowing it to boot...
so if you can, try to avoid using generic usb hubs, or try to use ones like the carnetix one-- that doesn't rely on regulated power and put strain on the computers psu(no, they are not cheap--hence the reason i don't have one either--i just slimmed my setup down to required items only).
otherwise, that board should be able to be powered by about any power supply but the pico-psu series(no 12v regulation or startup/shutdown controller). just try to use a psu power calculator to determine your approximate draw, and go from there.
overall, i have not seen any specific proof that any platter-based hdd is any better then any other version-- there was even a member that had a 3.5" drive survive multiple car-totaling wrecks... of course ssd is better-- both from a vibration-resistance standpoint, and in terms of read/write speeds, but 'worth the extra cost' is something that you need to answer for yourself.
personally, i ran 2.5" drives until i could afford differently..