[ghego1]

Dropbox passwords, although it still leaves something be desired, looks very secure.

For what I have understood they store on their servers only an encrypted version of the passwords data. The encryption key is randomly generated from 12 words, that are not saved on their servers. Each new client that you want to connect to Dropbox passwords must be authorized by an existing client. I believe that it is at that time that the key is shared with the new client (if approved).

Is there someone here from Dropbox that could confirm this?

As per security, IMO this is currently the best compromise between security and usability.