I don't think there's any reason to avoid black... generally we go for the wood-like finishes to put some colour in the room or to match some furniture already in the room.

If you look at the wall 'o fame there are a fair number of black speakers there so some people are definitely buying 'em :

http://www.axiomaudio.com/wallofame.html


M60ti, VP180, QS8, M2ti, EP500, PC-Plus 20-39
M5HP, M40ti, Sierra-1
LFR1100 active, ADA1500-4 and -8