Why are Macs so over priced?

I just customized an alienware laptop, too have an 8800GTX video card, a 2.4GHz Core 2 Duo, 2GB DDR2 memory, and a 1920x1200 resolution. Or I could buy a MacBook Pro, with these specs; Integrated Intel GMA Graphics, a 2.2GHz Core 2 Duo, 2GB DDR2 Memory, and a 1440x900 resolution. They cost the same price... On the AlienWare, you get the most powerful mobile video card, a faster processor, the same amount of memory, and a much higher resolution. 1440x900 doesn't even compare with 1920x1200.