I've talked with many stay-at-home parents who have used their time at home as an opportunity to reflect on and prepare for a new career. In searching out a new career opportunity, considering the flexibility of the work is important.
Yahoo recently published a list of the most flexible higher paying careers. See the article here. Being a college professor tops the list and I agree that it offers a lot of flexibility. You only need a Master's degree to teach at most community colleges, however, the pay often isn't great. Pursuing a Ph.D. can be worthwhile if you want a career as an academic. However, the life of a graduate student offers little flexibility. I had my kids after I had completed most of my doctorate program. I know people who have made it through a Ph.D. program while they have kids, but it is tough! However, the reward of a challenging but flexible career may make it worthwhile.