I don't think Dre is the best I don't give a fuck what nobody say there are too many good producers out there to say who's the best it depends on what is your style
Well there are a lot of contrenders for the spot. There are several worth mentioning:
JJ - he's bringing back the West these days
DJ Quik - never lost his magical westside touch
Just Blaze - this guy just knows how to produce period.
Timbaland - he has proved everyone he can work with anybody and the rap game and make his production on a rapper's album a pure classic (i.e. Dirt off Your Shoulder, Put You In The Game, etc)
But the best imo has to be RZA the true legendary producer that never received the credit he ever deserved. This guy is just a legend, having produced the score for movies such as Ghost Dog, Kill Bill vol.1 & 2, Blade Trinity and more. All this and not even mentioning whatever he contributed for the Wu Family. Didn't anyone think the Intro for Meth's Tical 0 was the best intro of the year by very far?