cannot see default civisualize displays in 4.6.10
check if you have any error message, eg about a missing d3 object

your error is most likely that the url for extensions isn't properly configured, so all the javascript needed to get civisualize working properly isn't there.

if you have firebug installed, or other developer extensions, you should see-in the net tab- that it's looking for the needed javascript at the wrong place