Canon 28mm 2.8 IS and 7D
thank you very much for your responses and I am going to look into this further I am thinking maybe the Sigma 30mm 1.3 but it does not seem to get the best reviews. for the price of the 17-55 I would rather buy a Zeiss 35mm f2.
from a pocketability .. it's not a bad choice (the 28mm 2.8) .. however the 28mm 2.8 non IS wasn't a slouch either.
I never had much luck with the 28mm zeiss .. so i'd stay away from that personally .. but from a small light convenience aspect those are probably your two main choices.
if you can handle the more archaic and possibly less accurate AF in the older 28mm .. i'd go with that.