I run a small project at an R&D lab that seeks to foster reuse of 3D content. We have a public facing instance of our repository software, with a few hundred models. Some of these are available for download anonymously, and others are only available for download after you sign up for an account, depending on the permissions set by the uploader. Signing up is free and easy.
After you've signed up, you can also upload models. I would really appreciate it if anyone out there could try this process. We do a few interesting technical things, like convert your content on the fly, and preview it with WebGL. You could also use the site as method to store your own content - it can be marked as private if you choose. You can upload content in 3DS, OBJ, SKP, FBX and DAE, and download as JSON, OBJ, FBX, DAE or O3D.
Even if you are not able to contribute any content, please visit the site. I'm keeping some stats, and more traffic will help us improve the product.
Also, in the next few months, this project will be available as open source software, so you can setup your own repository. Check out the blog on the site for developer info.
The address is http://3dr.adlnet.gov
Please let me know what you think by commenting here, or using the "Contact Us" page