Alexa , google and yahoo has there own ranking system. It is not necessary that google high rank page will be get high rank in yahoo or alexa. They have there own separate ranking system and method. So it is not much use to find other ranking sites. Just download and use fire fox and there is a tool that you will get the page rank of each page you are browsing. Just go here to download firefox browser.
http://firefox-details.blogspot.com/