A few days back I came across HotPads.com. What sets HotPads.com apart from other real estate search sites is the ability to use a map to identify properties. For example, if you need to purchase a condo around New York city, typing in Zip codes is a tedious way to find listings and you may very well end up missing a good property listing. A better way to find a property is to use the map based search service provided at HotPads.com.
The usual search criteria such as prices, bedrooms etc. are available also. I have a feeling that map based searches are going to become a standard for multiple listing services (MLS) and pretty much any online database that has entries associated with a zip code and address.
While most property listing show up pretty accurately on HotPads.com there are some quirks (here and there) where some properties from far away show up incorrectly. This is minor and I am sure will get resolved. Overall, I like the service.