I've done it both ways - with an early reveal and with a last minute reveal of the villain. Personally, I like the last minute reveal better. I like to guess along with L/C (or whomever I happen to be reading). When the reader is just as much in the dark as the hero/heroes I find that to be more satisfying. But that means I actually have to fully plot out a story beforehand - usually I'm operating off a very loose outline instead of a well-defined series of events. I do know who the bad guy is when I start out, but I try to put a few red herrings in as well.
I agree with you on how teeth-grindingly irritating it is to have to exposit everything when the villain is revealed. I avoided that once by having Inspector Henderson show up and explain the rest. Or you could have them writing up the article and clean up the loose ends that way.
My favorite color? Green - every shade of it. Except for puce.
