Dropbox is great when you need realtime access to your files. I have a free account and use it for syncning some music and important files between home and work.
If you're only using it for backup purposes, there are a lot of cheaper alternatives. I've been using Mozy (home vesion) for a year and it has unlimited space for $5/month. I don't get realtime access, but for backup it's great. As a bonus, their sync program lets you specify your own encryption key so they can't even view your file data (file names/directory structure is still open).
[Mozy's] sync program lets you specify your own encryption key so they can't even view your file data
... assuming you trust their security, that is. Given that they proudly advertise using blowfish -- an algorithm which even the inventor has expressed surprise that anyone is still using -- and they don't make their client source code available for audit, it's hard to place much trust there.
at some time you're gonna have to trust any cloud provider, irrespective of the encryption(/lack) or the implementation - you send ur data off over your dsl and it's up for grabs. simple as that!
If you're only using it for backup purposes, there are a lot of cheaper alternatives. I've been using Mozy (home vesion) for a year and it has unlimited space for $5/month. I don't get realtime access, but for backup it's great. As a bonus, their sync program lets you specify your own encryption key so they can't even view your file data (file names/directory structure is still open).