Since the A101 doesn't have a 250Gig version, some of us may be considering using a USB harddrive with our A101. It's not too far off since we do have a screen bigger than the A70 as well as being able to use it as a media player for out HDMI TV's.
So i tried putting in my WD Passport 320Gig and see how long it'll last from a full charge.
720p h264 videos
Screen brightness dimmed
Wifi off (Mostly, i was taking screenshots of the file details and sometimes forgot to turn off the wifi)
NTFS (Support for 8Gig 720p videos)
It finally shut down after five hours four minutes, plus or minus 10 minutes due to screenshot taking and wifi being left on.
Five hours on a mechanical drive seems pretty good eh? Note tho that i haven't actually tried running a battery test with it running off the internal memory, so i don't actually know how long it normally lasts.
Another thing is that the Passport is designed to run off a single USB port. Other external drives come with a USB-Y-Cable, the passport comes with just one. So the power usage may be different for the others.