Alexa, which reports numbers based on the surfing patterns of users that have downloaded their toolbar, says that Technorati is #1 in blogosphere search. Richard MacManus took the time to generate all the comparison charts. By the way, if you want to have a voice in these results, then simply download the toolbar.
http://www.readwriteweb.com/archives/002775.php
Update: Technorati's recent jump in traffic seems to have partially maimed their Website. I haven't been able to do much more than visit their homepage today