Since when was "Indie" bad word? Here is a website that features the artists that are still truly independent--and they have plenty of FREE downloads. My favorite kind!!! So far, I like Thunderhawk, but I haven't been able to listen to much else...yet.
Take your top 20 artists. For each of these artists, collect the top 5 similar artists. The resulting number of unique artists is your eclectic score. If the score is small (extreme = 5) your musical preferences are very limited, and if it is large (extreme = 100), then you have an eclectic musical preference. You can compute your own score at http://anthony.liekens.net/pub/scripts/last.fm/eclectic.php