Okay, thanks Admin.
So, on estimate, the most power drain I can expect is about 400ma (give or take a few milliamps).
I'll see how they perform on just my laptop via a bus-powered or self-powered USB hub (one with either option. That way, if I need to use an external power supply, I don't have to buy a whole 'nother USB hub.)
Thanks for all the input, guys!