Time To Unify Web Metrics?

There are lots of ways to measure the popularity of a social networking site. The general shift seems to be toward measuring engagement – how long users spend at a site and how often they show up. Even then, you'll often see the same names pop up that you would have if page views and/or unique visitors were measured alone. Time To Unify Web Metrics?
The top 10 are:

1.    Digg.com
2.    Netscape.com
3.    Technorati.com
4.    del.icio.us
5.    Fark.com
6.    StumbleUpon.com
7.    MyBlogLog.com
8.    reddit.com
9.    kaboodle.com
10.    Slashdot.com

It would be interesting to see a more overall view that added pageviews per visitor, average visits per visitor, session time per visitor, and some sort of widget measurement. Perhaps someone can give us an overall score based on the combination of those metrics.