I think it's all a matter of preference - most laptops that are made to be thin will be using intel's i7-2620 or 2640 which is a Dual-Core w/ hyper threading. Not a bad processor, but if you want muscle you'll want a 2nd Gen i7 quad.
What things do you want to be able to do on your laptop on a daily basis and what screen size would be best for you? That will be the most helpful to point you to a specific laptop