The Oster Professional 76023-510 Fast Feed Clipper is a mid-range hair clipper that produces a professional finish at a very reasonable price.
The Andis Ceramic BGRC 63965 is a top-end professional clipper that can be used cordless. It has a powerful, but quiet motor, and detachable blades that stay cool for longer.
The Oster Classic 76 is the professional’s hair clipper of choice. Read my review, and why I think it is one of the best hair clippers money can buy.