I use
rsync.net and have found them to be very reliable. As well as rsync there's loads of ways to access it, they also offer a geographically diverse backup plan, and support SVN as well as git for revision control if you're in to that sort of thing.
edit: I notice that it's a fair bit more expensive than spotvps, however a vps isn't as good as what they offer for backups. A cheap VPS is likely to run on single disks with little chance of recovery on failure, with sites like rsync.net your data is on proper filers with snapshots etc and much more redundancy.
