I would like a professional website created.

I would like to create a members only website using my already bought domain whereby people can create a small profile and a picture and download their ideas/creations/projects in the form of a word document, picture or file.
There will be two types of members, a normal user, called a 'Brainbox' and a Professional User, who can comment and make suggestions and/or proposals to further expand on their idea.

I would like a template that has both a business look, to attract professionals, but also that is quite a fun but relevant theme.

To start asap. Budget is negotialble.