With so many different interface types on external hard drives it must be hard for the average consumer to decide which is best. Heck, for a techie like me I even find myself puzzled sometimes. There is USB 2, Firewire 400 and 800, eSATA and ethernet. I suppose the easy option is to get a drive with all the interfaces on one unit, but that often costs a price premium. For a long time now, I have owned a 10/100 ethernet hard drive, a separate USB 2 drive and a triple interface (Western Digital My Book Studio). Having a new iMac on the way, I needed yet another drive for the daily clone of the new computer, so what should I choose?
To make things easier for everyone, here is a simple guide to what might be the best solution;
USB 2 - for simple file storage or a daily backup, where speed is not the highest priority.
Firewire 400/800 - if you are doing video work, or moving large amounts of data. If your end of day backup is very large, say 100GB+ this is also worth considering.
eSATA - in the Mac world this is only accessible if you have an adapter card in a PowerMac, Mac Pro, or perhaps a MacBook Pro. Useful again where speed is essential.
Ethernet - I would not recommend these for general backup use. However, if you own more than one Mac they are great for putting all your digital media (photos, movies, music) in one place.
I hope this helps... in case you are wondering, for my current needs I chose a triple interface MyBook again.