I've been pretty lax in backing up my photos. I have 82,595 files totally 450Gb. So, not a massive amount of data. I've had the files spread over three different drives and many files only in a single location.
I've put a new 2Tb drive into the desktop and for £79/year Amazon now allows you upload unlimited photos to the cloud which is by far the cheapest solution out there (that i've found).
What i've yet to find is a good app for automatically syncing my files betwee my drive and the cloud. What there is however is an SDK available so over the weekend i'll write something.
If you know of a good syncing app out there already then please let me know in the comments.