Christian Liberty Academy was what I started with and I really liked most of it. The nice thing with them is you can order a grade related curriculum kit to get started. I think these are good when you are starting in K or 1st.
Now I pick and choose from different ones. I highly recommend Learning Language Arts Through Literature. It is easy to follow and combines all the language arts into one book. This is so much nicer than having 3 seperate books to have to work from (Spelling, Grammer, writing, penmanship). It also throws in a little Math, Geography, Bible, History, etc... here and there and so it really adds flavor and gives that little extra punch to it.
For Math, I am using Saxon - I am finding this one is the easiest to follow for both the student and the teacher. I am not saying the Math itself is easy, but is best for explaining and helping to understand than what I was previously using (Modern Curriculum Press). Now that Ryan is in 6th grade, it is what I really needed because Math is a weak subject for me and he is doing stuff I don't even remember doing in High School!!! So I need something that could help me help him.
For younger students, the Cuissenare Rods and books are pretty good but a little weak on drill work which is neccesary for setting the concepts into the memory banks.
One that I tried that I really didn't care for was the A Beka books - at least the language arts that I had used for Ryan in 1st and 2nd grade.
No matter what you choose, never let yourself be a slave to the books. If something seems like it just doesn't apply to your children - skip it, find something else. Example, when Ryan was in second grade, the A Bekka language book I was using would have these really dumb assignments like write a story about a clock, or an animal in a store. Ryan is rather literal and he just couldn't picture a talking clock or other silly nonsense so I told him to write about what interested him. He was really into wolves at that time and was reading 4th and 5th grade level informative books about them, so he wrote about what he had read. This was so much better for him since he could apply what he had read and he enjoyed doing it too.