Re: External HD question
Hard drives are EXTREMELY sensitive to shock damage. It is most likely dead, even if the drive's electronics are still functional it is very likely that the mechanical part was damaged. You may be able to re-use the USB enclosure if it didn't smash into a million pieces, but the actual drive is probably dead. You could try removing the drive and connecting it to your PC internally (SATA or IDE port in your PC) to try and recover data. See what kind of drive your enclosure takes (SATA, IDE, or either) and get that kind of internal drive. Then just put the new drive into your enclosure.
If your enclosure is damaged and you need to replace the whole thing, I suggest buying an AcomData Samba enclosure (they support both IDE and SATA drives, have a fast USB2.0 connection, and are pretty well built) with a large SATA drive in it. Mine is a 1.5TB Seagate in that enclosure and it works very well.