I like 24 for full time feeding a newborn. I just buy the largest size and don't bother with the smaller ones, I didn't really need them. I love my Tommee Tippee bottles, especially if you're going to try nursing too.
We used plain old Enfamil. I would just start with a regular formula unless there are signs of allergies. They are pretty similar generally. Some newborns do better with the ready to feed liquid at first instead of powder.