If I ever get my MacBook Pro (I've been without a computer for 3.5 months since sending my Powerbook in to Apple for repair) I'll take comparison shots with it and my sister's MacBook.
I've owned a
Sony XBlack LCD monitor, and have been using my sister's MacBook for the last 2/3 weeks.
Go with a matte screen.
With the Sony XBlack monitor I had, the glossy screen was great as I was able to put it in a location that didn't get reflections, and it added a nice level of punch / depth to the image. (it was mostly used for watching TV/playing games)
The MacBook, however, is used all around the house, and I'm constantly repositioning it to avoid glare, and often end up using it at an angle, which is very annoying.
If you're doing any kind of image editing, or anything that requires accuracy, forget a glossy screen. If not, make sure you like sitting in the dark, or can move so that any light source is in front of you.
Here's some quick snaps from where I'm sitting right now. Browsing the web:
In the dark.
Light turned on.
Lots of people say the glossy screens are better for games. Well, they are and they aren't. They usually have richer blacks, and stronger colours, but most of the games I see these days often have a lot of dark areas, which I would imagine are quite hard to see with glossy. Here's a snap from a game trailer:
In the dark.
With the light on.
With a matte screen, these bright areas would be very diffused, and would just be a slightly brighter area, rather than making that section unreadable.
I don't know how it compares to the MacBook Pro screens, but colour isn't great on this (lack of accuracy - they're strong enough) viewing angles are very poor, and contrast is only measuring about 38:1 on/off. (it's not nearly as bad as it sounds) Perhaps it's just like this as it's a "consumer" machine, rather than pro, but my Powerbook was much better than that, around 150:1 if I remember correctly. (but it maxed out at 90cd/m2, whereas this can go to 190cd/m2, which is far better for viewing in a brighter room)