Recently finished work on Blackbird Homes, a real estate company in St. Petersburg, Florida.   I used WordPress as the Content Management System  and the Homeowner Theme by Gorilla Themes. 

The theme design is very clean and organized, but I was mainly impressed with how well the theme integrated with WordPress.  You can add a listing as easily as you can add a blog post.  The categories are used heavily to create search functionality, organize properties and distinguish between listings and blog posts.

The theme is user-friendly, including several useful plugins and 5 different color templates to choose from.

I could have built the entire site without any coding, but did tweak a few things on the sidebar, cascading style sheet and header.

The support forum at Gorilla themes has a lot of good information, the documentation available was easy to read and they responded to questions quickly.

The theme is scalable to allow multiple agents to have their own logins, post their own listings and have them displayed along with their agent profile.

I recommend this as a powerful, functional solution to a real estate website.