I would be concerned with HD access speed and rotational speed rather than size. I guess there are some 7200RPM 2.5" HDs out now and I would suggest them if you are going 2.5". Personally I would not do my editing off of a standard 4200 RPM external. Huiccups in data transfer just are not worth it. If you are really going to drive this thing hard with multiple audio and video tracks you will want to be careful. I would say iMovie would work ok on a 5400rpm 2.5". It's good that you are being cautious in your purchasing as so many people buy first and ask seecond. best -Preston > Think I can get a one comparable to the one below for under 24000 >yen? And if so, do you suggest a specific store? One of my bigger >concerns is the physical size: >>>http://eshop.macsales.com/item/Other%20World%20Computing/MEXPFW80GB/ > >Daniel