I use the Munsell system of color created by Alfred Munsell in his book A Grammar of Color published in 1924.
An artist mentor told me once, "Never use a color wheel from someone who wants to sell you paint." You will notice that the Grumbacher wheel has about 40 "colors", all conveniently matching their paints, but not very useful for learning color theory.
I actually found a copy of the original 1924 book in my local library! They got it in 1943 and it had been checked out about once every ten or fifteen years since then. The book had most of the color chits still intact and in good shape. A good copy of that 1924 book can go for up to $1,600 today.
Here is the wheel I made using his system:
http://www.fineportraitsinoil.com/Pics/Wheel.jpg