The Bose-In-Ear headphones are IMO the single worst product that Bose makes. The sound is awful, the isolation is terrible, the comfort is painful and the build quality is terrible.
For $100 you can find some much more preferable options, including the Shure E3's.
I wish that was true. The sad truth is that ALL Bose products distort sound and there is more bass then there should be. I've owned quite a few of their products and still do and if you want naturally sounding music Bose is not for you. Also Bose does not really play nice with equipment that is higher end than it. ( but that's not really a problem with the apple build in hardware )
As far as the original question goes, I'm assuming that you want the headphones for use with a notebook. Canals have shorter cords and they tend to be a little bit uncomfortable for notebook use ( at least for me ). But macbook has decent enough hardware and you will get improved sound with headphones in the mid to high range even with mp3s.