Jayko - Even so, PaB is vastly limited in the diversity pieces it offers, when compared against BrickLink which literally has nearly every single piece ever created in LEGO's history. I think the additional time needed to look for the parts you need is well worth it, considering how much money you will save in the long run. Quantity and quality is usually not an issue on BrickLink as many sellers have hundreds or thousands of a given piece in stock, and even used pieces are in fairly good condition unless the seller denotes otherwise.
I agree with you on the part limitation. I guess i've just never had much luck with bricklink myself. Even with a small model, I can never seem to find all the parts I need in less than 3 stores.