Yahoo Maps BETA was released recently. It was developed in Flex. This interface is so rich you just want to toy with it. I think the technology for Yahoo's map is better than Google's AJAX version, and I'm impressed. Particularly with the construction and traffic information that is integrated into the map. Browsing for restaurants, etc is very nicely implemented as well. The presentation layer of Flex makes my head spin it has so much potential.
I submitted one suggestion to Yahoo as feedback:
"...I'd like to be able to type in my start address.... then drag a marker on the "to" location my destination. ..."drag and drop"directions. Your algorithm would figure out the directions and the Flex/Flash interface would then display the directions.