I use an USB/Firewire case from compgeeks.com and some 3.5 160GB drive I picked up on sale.
These are now commodity items, so pricing can be cheap. Especially if you can use a philips screwdriver to put the drive in the case. About all I did.
You do have USB 2.0?
Can anyone recommend a good FireWire/USB 2.0 combo hard drive device. I just do not have sufficient space on my hard drive for these video files.