I'd go with Google Latitude, because you can embed it on your blog, and if you don't want to share your exact location, you can share an aproximate area (x square miles, yards, etc.). Here's a great post about it, hope it helps http://googlemapsmania.blogspot.com/2009/05/share-your-location-with-google.html

How about the Foursquare location map from Peek Maps?

http://www.widgetslab.com/2010/02/06/foursquare-location-on-google-map-with-peek-maps-widget/

This post will be useful, has a few for you to choose from:

http://socialwayne.com/2010/01/20/location-based-apps-widgets/

Some of the alternatives you have if you don't want to use Dopplr are Plazes and Bloglue

You can consider Brightkite as a good option. However, I would go with Google Latitude.

For me Whrrl is the best!

Check out www.YourLocalBlog.com - a hyperlocal map-based blogging network.