For a while now, I've been curious to know what the differences are in the Western Digital Caviar Series. So far as I know, Black is high performance, Green is eco-friendly and slow, but I'm not sure what the Blue series has to offer, other than a lower price tag. Can anyone clearify what the techinical differences are between Black and Blue? For high performace reasons, I bought the Black series for my tower, but what would I have been missing out on had I gone for the Blue series? Thanks in advance.