There is much debate on the ease at which you can return to work if you choose to "opt-out" and stay home. A recent article in the Chicago Tribute (see here), gave the perspective from both sides. Some say you can return to work, even after a significant leave, and just pick-up where you left off. Others say it isn't quite so easy.
I have to side with the latter. As an HR professional, I know many employers have big concerns with resume gaps. Depending on your field, a lot can change in just a few years and your skills and abilities can very quickly become obsolete. You may not have to start back at the bottom of the ladder, but you are most likely going to have to step down a few rungs to get back on. And those few rungs can be quite challenging to climb back up.
If you want to stay home, I think the best strategy is to have a plan of how you are going to stay connected in your field. Continue to attend professional meetings, network and read publications in your field. Take on some volunteer work to build skills. Try to find some contract work with your previous employer. The possibilities are endless. The key is to think about returning to work well before you ever actually want to return. The more planning you do, the easier you will find it to return.