I have used several paid online backup services including Mosy, MyPCBackup and JustCloud and a bunch of free services but about 2 months ago I signed up to SugarSync and have no regrets.
Sugar Sync backs up and syncs your selected folders, it has more features than Dropbox (which I haven't actually tried but have seen in action).
There is an App for Android and iPhone. The App allows you to stream your backed up Music library. It also has an option that automatically syncs photos and videos to the cloud. Videos are only synced while on wifi but photos can be synced on wifi and/or 3g.
There are a bunch of other features that some may find useful like the ability to share entire folders or just a single file and keep folders synced between PC's.
They have a free account that comes with 5gb of storage and a variety of paid accounts.
It's taken me years to find an online backup service that I'm actually happy with!!!!
If you sign up to a free account, sign up using my referral link below and we will both get an extra 500mb of storage. Sign up to a paid account via the referral link and we will both get 10gb extra storage.
Does anyone else here use Sugar Sync? What are your experiences?