Brown Sugar or Castor Sugar in Brownies?

Sugar is a big part in all baked goods, but to use brown or castor sugar in the brownie? Does it make a difference to the texture, anything? What i like to do is use er, a mixture of the tobas. I find that too much brown sugar can overpower the flavor of the chocolate. But yet, you can really experiment with brownies. It's such a great bass recipe to add your own little on. Some people are real purists about brownies and say, you know, just chocolate, like chunks of chocolate er. They always go down really well, and the salt really balances out the sweetness nicely.