Below are a few plugins that I highly recommend to increase your sites rankings. If your online presence is your main focus, then you might as well build the proper foundation from the get-go.
1. HeadSpace 2 – With the HeadSpace plugin you can tag posts, create custom titles and descriptions that improve your sites ranking. Short video below.
2. Property Watch – The property watch plugin creates a form for home buyers to email you their home search criteria. This works great if you do not have an IDX search on your website.
3. RSS Footer - This is a Great plugin by Yoast. This will enable you to get a link back to your original article post if (when) your site gets scraped.
4. Real Estate Theme – This is not necessarily a plugin, however its a great real estate theme by Brian Gardner. If your just starting out and want a web presence, there really is no need to spend 1000s on a website. Not at first anyways 
.
You have sparked some of my interest and I am going to do some additional research. Feel free to check out some my blog in the near future… as I just posted a great blog about the 36 Best WordPress plugins for 2009. thanks
I have read a few of your posts and they are all interesting and informative…keep up the good work.
Hi. Do you have a real estate plugin?
I want a wordpress to sell home.
Your blog is great and wanted to thank you. I am more interested in building a wordpress site for my San Diego omes For sale business than I ever thought I would be. Thanks and keep it up!
Take a look at this wordpress plug in for real estate. We are still working on it, but almost finished.
You can see a running website in this one at http://www.altijdzon.nl/domrep/.
You can find the plugin at http://wordpress.org/extend/plugins/real-estate/
We are working on the search now.
Its totally optimized for seo.
Not purely for “real estate”, but WP-Property is a good plugin as well. The demo site seems more “property management” oriented, and I only played around with it a little, but seems to work well. http://wordpress.org/extend/plugins/wp-property/