We are considering an eclectic mix, here is what I've decided on so far:
Story of the World
Excellence in Writing
5 in a Row
I purchased the subscription to Reading Eggs/Express and we are very happy with it so far. I am not sure if we will purchase a subscription to Spelling City, the free version seems to meet our needs at this point. The little girls really like Story of the World and have requested that I buy the Kindle version so they don't have to keep track of the book. We will be using Excellence in Writing, Apologia Science and Saxon Math through the co-op.
I will probably add more things as we get closer to the start of the new school year. I also have a ton of supplemental workbooks for the younger girls. I am tentatively planning to start August 20th. Co-op starts on August 26th.
Melanie will be doing mostly 2nd grade
Marissa will be doing a mix of 3rd and 4th grade
Maggie is a high school Freshman
Morgan is a high school Junior