I think it was torchiest that made a Peanut Butter Ale (can't recall for sure though). I think he had one heck of a time getting rid of the oil, but iirc he mentioned it turned out good.
Personally, I find it fun to derive those flavors (nutty, fruity, etc) from malts, hops and yeast. It is really fun to have someone think you put something into a brew, say like Cherries when you never did. 'Course there are some tricks to getting these to come through in the final product, but that is one challenge I *love* in homebrewing.