Other than Dropbox, what out there has been especially useful for storing and sharing game content like images during development (similar feature set to Dropbox like working offline, automatic syncing and support for windows/osx)?

We are looking into hosting our own SharePoint server but it seems to be really focused on documents... Maybe Box.net would work?

EDIT

For code, we are using Git.

To be more precise, I was looking for an easy, automatic way for content produced by artists/audio engineers to be available to everyone. Features like approvals of assets don't hurt either. Following the answer linked by Tetrad, Alienbrain looked pretty interesting but..is way out of our budget (may be something to invest in in the future).

What ended up doing...

We were going to go with Box.net but downloading the sync apps for desktop use required us to wait to be contacted by them for some reason. We did not have much time to wait so we ended up going with Dropbox Teams. Box.net has a nice feature set but we never really felt held back without them.

Thanks for the help :).