Just thought I would share what we are planning on doing this year in school.
The girls will be in 5th grade and my son will be in 1st.
Math - Modern Curriculum Press Workbooks supplemented with Math-U-See
Computer Supplement for Drillwork - Math Compass (Free Download)
The kids all enjoy MCP's workbooks. The Math-U-See I bought used and really like, but it's a little to much daily prep for me, so we will use it when we are struggling with a concept and need more hands on.
Phonics - Modern Curriculum Press Plaid Phonics and Word Study
Spelling - Modern Curriculum Press Spelling Workout
Writing and Grammar - First Language Lessons for the Well-Trained Mind
Possibly - Simply Grammar
Scott Foresman's Grammar and Writing Handbook (This is a free online PDF workbook. We have been using it this summer and have had very good results so far and you sure can't beat free!)
History - Mystery of History Vol. I
Science - Exploring Creation with Botany or Great Science Adventures : The World of Space
(I already have both of these. I just have to decide which one will work best for our multiple grade levels.)
For History and Science we will be using curriculum that is easy to adapt to multiple grade levels, so we can all do these subjects together.
At one point I tried to get away from using so many workbooks, but have found that my children missed doing them and they fit our lifestyle much better.
Over the years I have bought a lot of our curriculum for Rainbow Resource. I highly recommend that you order one of their catalogs. They review most of the things that they sell and I have found the reviews very helpful in choosing what to use. This is a very extensive catalog.
Lately I have been getting most of my materials from a nearby store (Wisescrappers) that a couple of my friends own together. If they do not have something in the store they will order it for me, usually with free shipping.
Be sure to click on the Blue names for more info.