Hey! Check out the Beta of Google Maps! Beats the pants off of any of those other mapping sites, IMHO.

http://maps.google.com/

Great navagation tools! Lots of cool details and touches.

U.S.A. & Canada only right now, I believe.

Very cool. I like the drop shadows for the markers. The maps are nice and big too. I'll have to start using that one instead of my usual Yahoo Maps.

Google is adding a Satellite View feature to their mapping service now:

http://www.pcmag.com/article2/0,1759,1782572,00.asp

Limited coverage and some of the satellite views are pretty dated, but still it's a nice option.