For backup, I use and recommend Jungle Disk, which backs things up to Amazon's S3 cloud (e.g., their servers). Costs $3/month + storage fees (first 5 GB free, then $0.15/GB per month) --

https://www.jungledisk.com/personal/desktop/features/

It's nice for two reasons -- an external hard drive will still burn in a fire in your house (gosh forbid), so it helps with having a copy of the data outside of your home. Second, you can access the files you backup from any computer, handy in case you need something when you're away from home.

Best,
DocJohn

PS - In case you're wondering, yes Amazon's S3 cloud is very reliable. Most of the images served on the main Psych Central website are done so through Amazon's cloud computing services.