This site has an incredibly broad selection of blues lyrics arranged by artist, title, and (most importantly) by topic -- including such topics as booze and metaphorical sex. Imagine a site that has the lyrics to 76 Big Bill Broonzy tunes and 88 from Lightnin' Hopkins!!!
The site also features a blues dictionary (which is a little bit weak, but at least they put in the effort...) and links to LOTS of blues tab sites, including both OLGA and fan sites.
Biggest negative is that the site is hosted by FortuneCity, so it's slow and ugly. But it's still a good place to waste a couple of hours for any blues connoisseur.