Interesting question.
It wasn't anything that we set out to do, many years ago, but have fallen into a balance that works for us.
My husband works. He pays the bills. He handles the finances. He takes care of the maintinance of the house. He ensures that my car is filled up and clean. He makes the kids lunches for school. He drives the 2 middle kids to school. He writes the big checks.
I do the laundry. I cook. I make sure the kids have what they need. (Cloths, shoes, permission slips, sign-ups for activities) I stay home with the kids during the day. I handle all scheduling. I volunteer for their activities. I homeschool one of the kids.
I also have a part time job. I don't "Have" to work, but it is my sanity time. While I am at work, he takes care of the kids that are home. (I went back to work 6 days after having my last child--and he took over) I have my own little account for that money. I buy the Disneyland passes, he pays the mortgage.
We both change diapers. Drive the kids to their activities. Attend big events for the kids. Take the kids to Dr. and dental visits. I usually do the ortho, and hubby does the big stuff, MRI's and CT scans. We just check to see who has the lightest schedule.
He does the dishes, and the baths...I comb, and style the hair. I fill out the forms, he writes the check. I schedule haircuts, Dr. appts, school conferences, lay the kids cloths out, and oversee homework; He takes them to school.
It's almost like a dance. We work well together. We never "planned" the division of labor, it just evolved.
I think if we had tried to "plan" who does what, it wouldn't have worked as well.