I chose to SAH for several reasons. First, I was never really "into" my job, it was just that (a job), not a career. We would have lost 2/3 of my salary to daycare.
This is pretty much our situation. I am planning to SAH as soon as this baby is born next summer. My job isn't worth the stress, long commute, and low pay to keep working. However, I'll probably end up going back to work part-time once we're done having kids and they are in school.
Also, in pursuit of the goal of me being a SAHM, we've lived completely off of DH's salary since getting married, with all my paychecks going into savings. It's a great practical way to make sure that this will be possible (and it definitely is!).