American Dream Realty Update

We are currently exploring the possibility of re-designing our site. It was create over 5 years ago and is pretty dated and needs to be brought up to this century. We are looking for any advise or comments as to what they think users are looking for in a real estate site.
What is the most important thing about a search? Is a map search a priority of a normal search results page? Should the search results page be displayed first for easy glancing and then a interactive map search as a secondary tool. Should the user be able to pick the frequency of the email alerts?  What other features are users looking for when searching on a real estate site?