I use a combined approach for back-ups of my photos and everything else.

I have a couple of name-brand external HDs. For me Friday is back-up day; all important folders get copied to both of them (the "belt and braces" principle) - this usually takes less than an hour.

I also use CrashPlan (Online Data Backup | Offsite, Onsite & Cloud | Crashplan) as off-site back-up - there are other entities which offer similar services. I see this as insurance against disaster - my house burns down, etc.

For a fee CrashPlan backs up all of my important folders every day. This was useful when my old laptop died (a fatal HD crash) earlier this year so I was able to recover everything which (doh...) I had not backed up to my external HDs.