PR and Alexa are useless. Although it looks good to advertisers and other websites.
I have seen websites with a PR of 5 with no backlinks, and traffic as low as 20 visitors a month.
So it makes your wonder, Does anyone really know what PageRank is?
Good example of pr 5 website with almost no traffic and backlinks.
http://www.aspenmlssearch.com/contact.php
I have seen others, this is just the most recent one.