Amazon has this nice service aptly named Simple Storage Service (abbreviated S3), where they aim to provide simple storage of data of arbitrary size, with high availability at consumer-level cost. It really is a nice design. And there's a REST interface setup for me to store my data!
And Jeremy Zawodny points out how using this service actually ends up to be cheaper (and more reliable) than having a home media server!
That puts the total cost for 5 years worth of backups [on a home backup server] around $2,275 assuming that no hardware breaks.
Switching to S3 could save me $587 over five years!