Data Marketplace theme (Document/dataset management) help

Hi all,
I’m looking to help a non-profit create an open data marketplace, similar to:
https://www.infochimps.com/tags/location
or
https://opendata.socrata.com

Basically, we need a file archive/document management system to show descriptions of files and offer downloads. Document viewing would be great.

Any ideas to make this look good?

Thanks!
Ryan