Actually, Centrino is a specific Intel chipset. The CPU in it WAS
a core 2 duo, until this year.
The absolute best laptop CPU right now is the Intel Core i7. The Centrino platform currently uses it.
Also, all laptop processors are designed for the job. The core 2 duo in a desktop is very different from the one in a laptop. Same for the i7. My laptop has an older('07, Merom) Core 2 duo, and I can get 5-6 hours of life out of it.
Believe it or not, how big/bright your screen is and what sort of wireless stuff is turned on can have a bigger impact on your battery life than your CPU.