Mozy is backup made easy. Create an account, download the client, select the directories you want backed up and then just leave it in the background. On a fast line I had my 2gb free account filled up in a few hours. Restoring files is easy; just request a package of files you want restored and a few minutes later you are emailed a link to download the package.
The unlimited version is $4.95 per-month which is peanuts really.
One thing to note is that this isn’t an Amazon S3 competitor. I can’t share my Mozy backed-up files with anyone else, I can’t even view a file “hosted” by Mozy. It is a backup service, nothing more and nothing less. For this it is much cheaper than Amazon S3.
One missing feature in the beta Mac OS X client I am using is external HD support. It is available in the Windows client but is “a few months away rough guess” in the Mac OS X client. Most of the files I want to backup are on an external HD so I will just have to wait. But the test I did with 2gb worked very nicely so I am confident the 150gb on my external HD will work fine too.