with dropbox you have to put all your files/folders in the dropbox folder.
No you don't, you can just place symbolic links (shortcuts under M$ speak) in the Dropbox folder pointing to the directory/files you want backed up, not really any more hassle than firing up a dedicated GUI and navigating through to find the directories you want to back up.
Dropbox $10 a month for up to 50gb, mozy cost me (1 month ago) $120 for two years (unlimited). No contest IMHO.
I never disputed that there were cheaper alternatives, although the client software has to work on your system (most likely use similar to
rsync under the hood).