Hi,
I have a 17 inch MacBook pro and a 15 inch MacBook pro. Both are decked out and both have the matte screen. I also have an 11 inch MacBook Air ultimate.
(If you're wondering, the 17 inch is my personal computer and the 15 inch was supplied by my company.)
Of the three, my favorite is the 11 inch MacBook Air. But, it's not the most productive. Allow me to continue.
The 17 inch has the 1920 x 1200 screen, the 15 inch the 1440x900. That's very significant. For me, it's about pixels, not inches. When I'm developing software, I want the 17 inch. The 15 inch is nice, but it's not small enough to be useful on a plane, etc. So, the extra 2 inches doesn't matter. The 17 inch still fits in my backpack and I lug it around without a problem.
I would never buy the 15 inch when the 17 inch is available for only a couple hundred more. Never, ever.
I love both, but I love the 17 inch more.
Which leads me to my Air, which I'm typing on now. It's the thing that I still say "wow", every time I pick it up. The size is perfect for traveling, bringing to bed, sitting in a chair, on a desk, you name it. I have a coating of Invisible Shield on it; I do this with all my computers... I like the extra gloss, but also the slight tacki-ness it gives to the air when you grab it. I would hate to have it slip out of my hand. Everyone agrees it looks sweet and is functional. I know, I know, you're asking about the 17 vs 15. I digressed.
To answer your question: Get the 17 inch. Matte screen.
-VTPete
P.S. I DO like the "glossy" screen on the Air; it's much, much, much less reflective than the edge to edge glass of the MacBook Pro 15/17. Ok, I digressed again.