Does anyone have any suggestions on what to get and where to buy? My internal hard disk is currently a minuscule 80GB. I recently bought a 320GB external for backup purposes and I wondered whether I should buy an internal that exactly matched that capacity (I heard Time Machine works better if there is more space on the external than the internal?). Amazon sells some cheap ones made by "Generic" at around £40, would any of these do the trick? Any advice appreciated. Thanks!