Primary Function Directory (Not a Blog)

Hi
Help appreciated. I am reading the documentation, but overwhelmed.

If my primary function is not to operate the site as a Blog, but instead as a Directory for experts in a particular industry field is there a preferred THEME that I should use that would work better?

Here is general overview of the kind of functionality I intend for the site so is there a preferred type of theme that would work best:

>Account profiles (Experts) have searchable characteristics
>Account Profiles (Experts) can also be defined as either buyers, or sellers
>Experts (Buyers & Sellers) are searchable by categories, sub-categories, communities and tags
>Visitors (non-profiles) can search for Experts (Buyers & Sellers)
>Experts can search for Experts (Buyers can search for Sellers & visa versa)
>Account profiles (Experts=Buyers=Sellers) can list jobs specifications
>Only premium account holders can make job listings
>Visitors & Experts can search for jobs specifications by categories, sub-categories and tags
>Experts (Buyers & Sellers) can message one another
>Profiles can be edited as can job specifications
>Profiles & job specifications have different display formats

THANKS

DAVID