I know there's one in Herndon that does a great job. They walk you through it and discuss everything with you [style and such].
I take Truffles to
http://www.caninecarousel.com/ 4x a year. I take him to do major cuts (seasonal). I take him to petsmart for just a quick trim.
I know people have mentioned that petsmart isn't that great, but I have yet to have a bad experience and everyone loves truffles there.