Okay. You have too much spare time. :p
As for genres, I think we had
a very good discussion going on here about genres. Admittedly they're really stupid genres, but it certainly can't hurt to have some dubcore in your collection, can it?
Apart from that, the problem with genres is: Either you apply genres people agree with - in that case it's really broad (Rock, Pop, etc.) or you go into sub-genres and people who will download from you will think "What an idiot, $Band are certainly not $genre." and you'll never have everyone agreeing with you. Also, making things even worse, there's no guide so you would have to decide for every single band individually.
Of course, this could give us stuff to argue about until the end of time, in case you want to us to discuss about all these bands.