I know several pro photographers who works with a macbook. Stop kidding yourself, lightroom and photoshop works perfectly with an integrated GPU. Thay have a glossy screen and they don't whine like lillte spoiled child.
Well, if you go that way, Lightroom and Photoshop also work perfectly fine on a PC under Vista, they do come with matte screen and they cost quite less than a MBP (or even a MB)...
I would rather use these tools on a Vista PC with a matte screen than on a Mac notebook with a shiny display... The loss of pleasure and ergonomics from the later is just too high a price to pay for a somewhat nicer OS.