You've got to do what works for you as a family. My DH looks after our son (he also works one day a week as a nurse) and I think that he is a fantastic example to our son. I work full time as I earn more money, but I have chosen to work my hours and get in early (rather than the silly ones I used to do), so that I can get home for 4.30pm and spend some family time together.
I would suck as a SAHM, but love being able to dedicate all my time at home to my son. In an ideal world I would work part-time, but that can't be done at the moment.
I think your ideas may change after the birth, but as long as your child is loved and nurtured everything else will fall into place.