I just really want to avoid using anything but a single USB port for power. A flash drive would be ideal, but I need at least 40GB and that's still not very practical with flash media. If I can't guarantee that the drive will work on ports that can only supply 500mA, I'd rather go for a 1.8" one that will, but those are fairly spendy too, compared to 2.5" drives. All the 2.5" drives that I've been able to find specifications for require 1 amp to spin up. Do you think it's even possible that a 2.5" drive can spin up on 2.5W, or is it just not feasible?