I am trying to purchase one of these but confused about what I need and where is the best place to get one from.

I want somewhere to back up all my PC pictures, music etc as I lost everything and never want it to happen again....(PC was reformatted and everything lost - friend did it!)

Anyway I have been looking and seen HDD, SATA, IDE and I am confused.

I just want somewhere to save everthing and ideally just plug and play