Flash Drives For Backup?

I'm thinking about buying a usb flash drive in order to back up the family pictures. Though I'm not sure if that would be a good idea. Supposedly flash drives last longer than hard drives since there aren't any moving parts inside them. I don't know. I'm don't have a lot of faith in something so tiny and portable. It seems like they'd be easy to lose or step on or something. Has anyone ever had any experience with flash drives beyond an mp3 player?