For dark spots or acne scars, a stick foundation is best. It perfectly camouflages discoloration and blends so well that you may not need any concealer.
For skin in good condition, try just a tinted moisturizer or sheer foundation.
Oily or acne prone skin, use an oil free foundation that prevents mid day grease, and leaves you with a beautiful matte finish.
Combination skin, there are balancing foundations which mattifies the T-zone and hydrates the dry areas.
Now the biggest tip for African American women when it comes to foundation... rarely should you use just one foundation. You should really use 2. Lighter in the center of the face, and darker around the outside of the face (by the hairline, jawline etc) Makeup sure you then blend WELL!
Concealer would normally tend to be one shade lighter than your natural skin tone, and you would need to apply it AFTER your foundation. You may find that you don't even need it. Also yellow based is the most flattering.
As far as a powder goes (to set everything) a yellow toned is most flattering and natural.