I use sugarsync, and I love it. Versioning, instant sync across computers as files are created/modified, web access to files, public sharing via web, stream music from online storage via website.
I have FIOS, 20mbit upload, so I could to 1.5TB/week if I saturated the link, but actually you will be limited by the backup service throttling ;-)
Anyway I only have 30GB storage, which is plenty for documents and pictures. If you want to backup media, its pretty static so just get a few 2TB drives and a safety deposit or a fireproof safe in your closet.