Most any USB or FireWire Drive will work, the problem is ones that come at a cheap price are just that, cheap and unreliable.
Plus if your going to move your iTunes Media and iPhoto Libraries to an External Hard Drive, you really need to have a second External Hard Drive to backup your Media and Libraries on the first.
See > iPhoto: How to move the Library folder to a new location
and > iTunes for Mac: Moving your iTunes Media folder
Plus you really need to try and free up at least another 10GB or so, so that you do not run into trouble trying to move your iTunes Media and iPhoto Libraries.
Message was edited by: den.thed
Sorry babowa for barging in, I didn't see your second reply. Hope at this point you don't mind if I leave mine up as well. Dennis