You are right about Google docs. I am also used to the web interface. I am not sure if I really have a use for google drive but I am trying to find one.
I use cloud services for just about everything (Google docs, google and amazon music, git hub for code) so I don't really have any personal files to upload. Even pictures that I take go to Picasa or I just email them with GMail and they are saved in there.
I do have some movies on an external drive but it seems like the files would be too big to upload to a cloud drive. I was thinking I might try scanning hard copies of family documents and putting them on the drive. I would have to replace my bubble jet printer from 1995 to do that though.
The one really useful thing I have done with drop box from time to time is sharing documents with other people.