For work i travel around a fair bit & want it to lug around my movies inside a external hd case.
Reading around theres definatly a few problems being had tho
http://www.newegg.com/Product/Produ...g=-1&PurchaseMark=&VideoOnlyMark=False&Page=1
You can fit approximately 625 movies on a 500GB hdd. No way you are going to watch that many in a short time.
Also, copying between drives is a lot faster than copying to and from the same drive, although this doesn't seem to be your concern, if you want to use it for mobility.