I think the Apple laptop with the longest battery life is something like 8 hours, right? There are numerous longlife laptops out there, and since they're all from various other manufacturers, they run Windows. Most netbooks run for at least 6 hours, many more and other ultraportables run for 10 hours or longer.
The operating system has much less to do with battery life than the power consumption and battery technology in the laptop. A MacBook Pro running Windows 7 will probably still get about 7-8 hours of battery life.
Silly fanboys.