The topic 'on being a genre obsessive' here got me thinking: In the past a lot of genres that were being attributed to bands (and vice versa) was sitting very uncomfortably with me.
As it's quite often not really possible to fit bands into any definite genre because of change of style from one recording to the next and generally over time, perhaps it would be interesting not to categorize bands but their individual albums instead.
Of course this would be a hell of a lot of work, but the fun and debates might make it worthwhile. But then again, I'm quite mad.
Some possible approaches might be:
1) Make a list of existing genres (step one) and attribute the albums to the appropriate one (step two).
2) Take albums and build a genre list while going along.
I bet the second method would generate quite a lot of surprises, not just concerning the amount of possibly 'new' genres, but also in how much we might have to adjust our perspective about the genres we've been slotting certain bands into in the past.