On a laptop I prefer glossy because I use them a lot on the road and the glossy screens are easier to clean fingerprints and dirt from than matte. The downside is that viewing a glossy screen in sunlight is a major PITA.
On a machine kept indoors, especially one that I'm going to use for photo and video editing, matte is the only way to go, in my opinion. If you look at all of the high end screens such as NEC and Eizo, they're matte. And that's for a reason.