I became a vampire from the guy in the dark brotherhood. I didn't like the vampirism, so i sought out a cure. I did the cure vampirism quest, and when the count gives u the reward for helping his wife, the reward conversation is still there. I select it again and i get the reward again. i now have 200,000 gold! Woot!
cool but not necessary. At the beginning you lack money, later on you have to try hard to purchase houses and furniture, and then you've such god forsaken loads of money, you can't even spend them.