When I went back to work (part-time) after (most of) my maternity leave, my DH took the remainder of the year's allowance and then went part-time too; so we both work 3 days, and both care for our son 2 days, with one day of nursery to cover the day we both work.
This seems like the ideal solution to us - both get to spend time with our son, both keep our careers going. I wish it were easier for more couples, if they want to, to both work part time and both do childcare. But I think that society needs to change a lot, to regard part-time working as a suitable option, for men and women, to consider childcare something both men and women can/ want to do. (I don't know if its a reflection of DHs workplace, or the fact that he is a man - very hard to draw conclusions from 1 person - but he has had far more stick than me - suggestions that he is unmanly for wanting to care for his child, a shirker for wanting to go part-time, etc.).
Now I'm being made redundant - company folding - and all the roles I am likely to want to apply for are full-time. We had the perfect solution (for us) and its only lasted a few months. 
I'm not sure where this ramble is taking me - except to say that I think SAH-ing is a viable/ desirable option for some, as working full-time is for others, but I wish there were more chances for both parents to spend time with their Dc(s) and work - and that the whole discussion about children, childcare, childcare costs, how much of a salary is 'eaten up' by childcare costs, the effect of nurseries on children, the effect on work, the effect on careers and the choices people make about all of these wasn't always portrayed as being about 'mothers', but instead was about 'parents'.