If S has an obsession, it certainly is with MAC. But if you want to know my secret, it's definitely within POP. The UK-based company has a plethora of colors to choose from and is certainly excellent with their color combos.
I found it about two-and-a-half years ago, as I walked around a Sephora in Soho. I was just wandering around when I came upon these round palettes. Each "Eye Cake" had five different colors that would be perfect to create the right look, either night dramatic or day subtle. Right there you had your base, your crease, your outside corner, your inner corner, and another light color to use for blending purposes. It was conveniently packaged together and gave great meaning to eyeshadows done right.
POP has since expanded to include larger palettes with 12 different shadows that are perfect for blue eyes, green eyes, and brown eyes. Shadows are really important because they can bring out the color of your eyes. And though some people I know think makeup is really just a mask, I think it's a great way to enhance the features you've already got. It's within moderation, and with the right products that you really can play up your best features.