Richard Dawkins is probably a little overrated, but he's a reasonably good biologist and an excellent popularizer of biology. I agree that his whole 'evangelical atheist' kick has been a bit childish, and that this is the source of a lot of the recent publicity that he's gotten. So not all of his fame flows from real, strong contributions to the field. But both The Selfish Gene and The Extended Phenotype are top-notch popular books, while at the same very influential in evolutionary genetics.
Yeah, his view that selection ONLY takes place at the level of the gene is probably overly reductionist, but he definitely pushed the field forward by clearly articulating the strengths of that view. As for the extended phenotype stuff, I'm not generally a fan of a lot of the work that has spun out of that (things like 'embodied cognition' etc) but it was an important and influential idea.