Exposed Beams

I'm doing a renovation of an apartment and most people I have shown it to think new ceilings are in order. I'm considering just ripping down the sheet-rock (or whatever is up there) and showing the exposed beams. This is a brownstone (built 1910). My questions are: - Is this cheaper then ripping down the old ceiling and putting up another? Obviously you save on materials, but is there some cost I'm missing here? - Is there anyway to sound proof with exposed beams? Can you put some sound proofing material between the beams? If so, is this more or less expensive then just putting up a new ceiling? - any code issues? - Is there anything important that I am overlooking?