Matte. Matte. Matte.
You can't accurately edit photos on a glossy screen. They may look really nice, but they brightness/contrast and color will be WAY off if you look at them again later on a calibrated non-glossy screen. Apple says the new MacBooks are fine, but from what I've heard from people who've played with them, in addition to my experience with them in the past, they are not acceptable as a tool for editing photos.
My girlfriend has a MacBook (glossy screen) and I have a MacBook Pro (matte screen) - there's no comparison. The photos I edit on mine (calibrated) look good on anything I look at them on. If I edit a photo to look right on her computer, it will look flat/not-contrasty on another monitor (my laptop or an external monitor).
The 17" MacBook Pros will continue to offer the matte screens, which a lot of people are speculating is because those are a popular tool for photographers and graphics professionals, and that group would not be happy about losing their display quality.
You may be able to get a 15" MBP from an Apple store cheap because of the new models coming in - worth checking out, or the refurbs on apple.com.