I recently started [url="http://www.gamebanshee.com/forums/showthread.php?t=70884"]this thread[/url] in the FR section because I am considering starting an evil Underdark campaign.
Consequently, this weekend I went to my local Barnes and Noble to maybe consider buying a little reading. After being (a) dissappointed by the lousy selection (it is a huge store on 59th street in NYC, for goodness' sake!) and (b) shocked by the sticker price of D&D suppliments now ($32.50!
I'll admit, a big reason I bought it was that the other, more relevant supplements weren't available. However, I have to say that my impression of the BoVD after a few days is incredibly positive. Evil is a hugely important factor in any rpg, but especially one as manichean as D&D. However, I think it has gotten short shrift in the past. As a (relatively) mature gamer (at age 23), I think that the BoVD is very well done. It deals with taboo topics (like sacrifice, addiction, and torture) that are a huge part of what evil characters do but that are typically not discussed in any depth.
Anyway, that's my proverbial two cents. I thought I would throw it out there to other gamers (esp. other DMs, as it is a DM reference book) and see what others thought. Does anyone else use the book? Do you like it?