It also depends on the stakes. In micro stakes I thing 5-10bb/hr is good but the variance is usually much higher due the number of fish. As you get into the mid stakes 5bb/hr is very good but variance is less. Also, you have to take in account that higher stakes and lower bb/hr win may mean more profit. So if you make 10bb/hr at .10NL you are making less than you would at a tougher $1NL game at 3bb/hr.