RE: Noise/power supply
Speaking from personal experience, my Freecom Mobile Drive XXS (admittedly the 250Gb version, though I can't imagine this making much difference) will happily run, on a single USB cable, from a Samsung Netbook... thats ALSO with a USB bus powered Hercules DJ Mix Hardware controller (4 channel audio in and out soundcard, and midi controller) >AND< an el-cheapo USB bus powered scan convertor. So I imagine even the limpest of USB ports would have no problem with the drive. Actually, I've just checked and according to the USB Root Hub Properties, it consumes 96mA.
The drive, even in a quiet room, is, as near as makes no difference, silent. The only noise being what I presume is a slight click when the head(s?) are parked after a period of activity. I've no idea if the rubber is a good conductor of heat but the drive never gets even warm to the touch, even after being used for hours on end.
As for vibration, if you pick it up you can tell something whirring away in there but I certainly wouldn't call it a vibration.
Hope that helps :)