Whoever says Brook is almost only a comedy character must have missed the part about him, you know… going slowly BATSHIT INSANE on a rotting ship for almost half a century. Or the "I'm a creepy skeleton and no one will ever recognize me / want to have anything to do with me" internal freakout moments. The jokes are pretty much his way NOT to think about it and pretend everything's fine.
Once you know that, they just aren't as funny...
Of course, there'll still be people who vote for the MOST! POWERFUL-EST! CHARACTER!, but honestly Brook's strength is far more than just raw fighting power. He has mad emotional resistance skills. What he went through? You'd all have committed suicide halfway through. Actually, not halfway through. I give you a year, at most. :U
Also, he managed to get a bunch of mourning, poisoned guys to die singing with a smile on their face. Now that's badass.
I don't hate Rayleigh, but I don't think he can compete as a character. Say what you will about the Straw-hats, they're still usually the most developped characters around, and therefore, at least to me, the most interesting. Not asking you to share this opinion, mind you.
So yeah, vote is going to the Sunny's resident skeleton, who, as someone pointed out, has been a pirate since BEFORE Gold Roger even started the pirate era.
Anyway. Don't take anything I said too personaly, I just sounded way too serious in that post. XD
(also, Brook has absolutely fantastic outfits. /best point ever)