Very well said, kevinshorses!
Clinton Anderson is one of my favorite of the name brand NH trainers. I've used his groundwork with great success on a more "hot and nervous" horse, and on a more laid back horse, and got great results with both. He's a great "people" trainer; I hauled my mom (she's not really a horsey person, but she's awesomely supportive of my obsession, ha ha) to one of his trailer loading demos once, and she said afterward that he explained what he was doing wonderfully, and she really understood what he was doing and why.
If you're looking for a "trainer in a box," CA would be pretty high on my list of recommendations. A big part of that recomendation comes from the fact that his TV show is somewhat informative (while no one can become a trainer by watching a TV show...) and educational, as opposed to the standard "info-mercial" that many other trainers have.