If you are a pro working with photos, or a not so pro, matte or glossy shouldn't be a problem for color choice. Seriously, are you going to fully trust apple with your work? The matte screens are good, but every screen is different and you will need to do a real color balance on the screen with something similar to a spider that can read the color temp and balance. Once done, either screen will be accurate, though the ultimate range slightly better on one or the other, depending on what colors are filtered by the screen, but I doubt it. If you want to know why this might be, post up but I guess most people won't care about the technicals.
The choice between the two screens should be based on where you expect to use it, and who might see the information on your screen. Personally I am a bit torn as I work with proprietary info and a matte screen is a better idea for making it slightly harder for others to see. Then again I travel extensively and there are plenty of times where I want to watch a movie on my screen, and the matte on my thinkpad just doesn't have enough of a contrast ratio.
Hopefully the new MBP, when it is released, will have a high res, high contrast ratio, high bit depth screen vs the standard lcd we all have come to know and love (0-255 vs 0-65536 per color) which would be better for blu-ray and hd-dvd. With both a matte and glossy option, of course!