That sounds very similar to the way I ride - usually about 3ft. from the curb. I figure that's the optimal position for making my intentions obvious, clearly indicating that I'm claiming my spot in the lane, but still being courteous so that it's easy for drivers to pass me with a safe margin.

But like Wolfchild, I react to road conditions as needed - if the situation means that any driver trying to pass me is likely to run me off the side of the street, I will take the whole lane so that nobody is tempted to make that unsafe pass. Potholes, an available safe shoulder, blind corners, different kinds of turn lanes and merge lanes, or traffic conditions are all things that effect my lane position.