I have at least seven different kinds of granite in my house. None of them, light or dark, has ever required any kind of maintenance. No, I don't seal them (not after I went to Europe and saw hundreds-of-years-old stone, which certainly never saw any sealant) (not to mention my friend's house, where the sealant peeled off).
This is the granite I have in my kitchen (no, this isn't MY kitchen:
Viara Granite <I>Vyara Granite)</I> Picture )
I did NOT seal it (despite what they say here). It has not stained. I abuse my granite ("you can take it for granite") and have not had any problem.