I agree with goddess27 that Urban Decay's Naked 2 has some killer matte eyeshadows. the brand also has many individually sold eyeshadows that you can choose from in matte colors. also check out Bobbi Brown's Ultra Nude eye palette
I have to admit, after buying the Naked palette (first one), I've just fallen in love with the Naked color. It is my go to base on top of their primer, and it is a great lid neutralizer. The best thing: absolutely matte. Another color from the palette I enjoy is Buck. A few shades darker, but just as wonderful and very matte also. I would NOT suggest buying the first Naked palette, though, because it does contain a lot of shimmers and glitters. The Naked 2 I've heard has many more matte colors.
Hope this helps!
I agree with the previous posts that Urban Decay has great neutral matte colors, especially in the Naked and Naked2 palettes.
However, I doubt that you want to buy a $50ish palette for two shadows.
The Urban Decay Matte Eyeshadow is a single eyeshadow for $17.
My favorite shade is Naked. It comes in the Naked palette.