I do use a NAS drive which is located across my parking lot in another building and I just set it to autobackup using AC's utility. The compressed files are less than 4.2 gb and that would allow me to restore all files including my imported items. I am lucky with the other building and such, but thumb drives that are 8 gb are getting cheaper and I really don't think it is worth scrimping and not backing up everything given a chance.
