Take your top 50 artists. For each of these artists, collect the top 20 similar artists (where the artist itself is the #1 most similar). The resulting number of unique artists is your super-eclectic score. You can compute your own score at http://anthony.liekens.net/pub/scripts/last.fm/supereclectic.php
My super-eclectic score is currently
720/1000
The most similar artists for my profile are 16Volt (6), Chemlab (6), KMFDM (5), Cyanotic (5), Nine Inch Nails (5), Sister Machine Gun (5), Rabbit Junk (5), The Shizit (5), The Horrors (5), Alice in Chains (5)