Clayton,
I whole heartedly agree. Color charts are invaluable. I first learned about them from reading Richard Schmid's book Alla Prima. I then spent the next two days making my own color charts. I keep them readily available next to my easel as can be seen in the studio shots posted here:
http://forum.portraitartist.com/showthread.php?t=8854
I also did some charts to study other color mixtures especially browns and grays. They are a great time saver and they are indeed attractive to look at.