I've been mining solidly for a week about now. I happened to have a 6870 already, without having any thought about mining.
I have made about .18 BTC and lived with a lot of noise and increased power. It was fun, but the way the market it is, I feel that I could make more money on an exchange...
But then we have the problem with the exchanges charging 0.6 % per transaction, which comes down to 1.2 % per trade.
Now that is all fine and good as long as the bitcoin is flying all over the place, as soon as it doesn't though...