Need Website Built - Can Lead to More, Very Lucrative Opportunities

I need help building a functional website where I can add different groups to it, with sub-groups as well, and let end users register adn upload pics, contact info, and descriptions, upon approval from site. Ecommerce capabilit for memberships and sales may also occur through website. possible expansion to advertisers as well. Need freelance programmer who can create the site using best possible application (wordpress or other interface?) so that I can update site myself as needed from time to time. Site must be expandable and able to handle a lot of activity as it grows (hopefully). It does not have to be overwrought with flash, etc.,, but it must look modern and professional. Must enter into confidentiality agreement. Could very well lead to additional opportunities.