Within the last couple of weeks, Yahoo has launched their beta web mapping application. It's a great AJAX implemetation, and is pretty amazing. You can search for specific categories of services, stores, etc. at any point during your session. I think it's pretty cool that you can zero in on an address and then say, “Show me all the ATMs in the area.“ Pretty handy. They even go a step further and add the contact info. Very nice touch.
Other cool things? Live traffic data, for areas that support it. Cool.