Another vote for it can be hard to make plans for a hypothetical baby. Feelings can change once you have him or her in your arms.
I will give you my story though.
I worked part time after my 1st DD was home (after 4 months off.) For the 1st few months I worked 2 1/2 days a week. My mother took one day, MIL another and DH was home on Fridays. This worked out well for us. Part time does really feel like the best of both worlds. I really recommend it if at all possible. I know many teachers job share. She went to a in home day care when she was 7 months old.
When my DD was almost 3 years old I was laid off. I loved my job, but I really always wanted to be at home. I decided it was time to do that. I also found out I was pregnant a few days after my job ended.
I love being at home now.
One thing to consider about day care is illness, it can be hard to find back up when you child is sick. It is so much easier now knowing that I can keep them home and give them mommy love when they are under the weather.
Before having children of my own (and before going to grad school) I spend many years working in preschool's and child care centers. Something I noticed is many times the more hours the child spends at the day care, the more needs and sometimes behavior problems they had. I mean the kids who got there at 7:00 am and left close to 6:00 pm 5 days a week. Then they came home, ate dinner (fast food?) and went to bed. After all they had to wake up at 6:00 am. That just isn't enough parent time and time to unwind. Days cares can be pretty crazy with many other kids and not a lot of individual time. So if you do the day care rote, try to work it out that they don't spend 8 hours a day there if at all possible. (at least not 11 hours a day.) One parent take them in later, one pick them up earlier is something many parents do.
Oh and if you do work, you still can breast feed and pump.

I have heard being home for at least 4 months helps to establish your supply.
Also consider how much of yourself you have to give to your career. Mine was rather intense (clinical social work at an inner city outpatient mental health clinic) I loved it, but it really took a lot out of me. It was hard to juggle them both. I think when the children are older I will be ready to go back to work and have more of myself to devote to it.
Best of luck.