I recently bought a Macbook pro 13" and I mainly wanted to use it for recording my bass guitar and digital piano. Both of the instruments could be connected directly to the computer I think. But I often saw threads saying that people buy external sound cards for recording. I start to wonder whether the internal sound card in the MBP doesn't deliver good sound quality or there is some other reasons for people to buy the external sound cards... If I need one as well, does anyone have any recommendations?