It would be great to have an integration with Dropbox. This could help to create a perfect user experience in terms of file handling. Here are some cases:
1. When creating a new customer in TeamGrid, TeamGrid could automatically create a customer folder in Dropbox. This also works with project folders.
2. When uploading a file to a project folder, the file automatically appears in TeamGrid. I think this is the most valuable advantage of such an integration. :)