Klyla

I'm about to buy an external hard drive to back up my system. I am not very geeky so I'm confused (yes I read the stickys) about what format I need.

My system is an HP Pavilion about 5 years old. I've got a 40gb drive and a partitioned 120gb drive.

I know formats keep advancing and I don't understand what kind to buy. Is an SATA compatible with my oldish PC? Or do I need an IDE drive...or what?
I see some Seagates and WD's on ebay that look interesting but I see IDE, SATA, SATAII and don't want to end up with something not compatible.

Second question is whether to buy one of the HDDs that have a "one touch" backup software included. I'm only going to be backing up about once a week, don't have a ton of pics, videos, music, etc. Just some home-based business stuff in Quickbooks, and typical household stuff. (We are not gamers either.)

Any recommendations on size and my other concerns would be greatly appreciated. I don't want to overbuy (I suspect a 500gb is overkill) but I also want a place to store my digital pics from vacation trips, birthday parties, etc.

TIA!