It's fairly accurate to say that with a warm and a cool of each primary you can mix almost anything, but reds are a different story. Certain reds are necessary to get good pinks. Some of my fave's are Thalo Red Rose (Grumbacher) Quinacridone Magenta (WN) and Quinacridone Red (Utrecht).
Bright sparkly reds are some of the important Tools of the Trade for me. Check out this month's Girls Just Wanna Paint blog for more paintings of 'tools'. Also, our GJWP show at Duxbury Free Library is up through June so go take a peek ;}