One simple thing that would instantly improve Google Docs would be the ability to upload files directly from OO to a Google Docs account. While this can be done pretty easily right now, the big issue involves Google Docs modifying the file after it is viewed in the editor. If you can store an exact copy of a file from OO or MS Office, that would give people a huge incentive to use Google Docs as a backup service. Later, as the program leaves Beta, people will make an easier transition to editing their files on Google's platform.
Right now I avoid doing this since files don't come out the same way they were put in, it's better to email myself a file in order to ensure it doesn't change.