What one drugstore beauty product do you absolutely depend on the most for your day-to-day beauty routine?

My answer's easy: Maybelline Define-A-Brow eyebrow pencil in Dark Blonde. It's one of the only drugstore pencils that is light, but not too light, and doesn't have any red in it at all. If you've got dark blonde/light brown hair, you know that eyebrow colors at the drugstore that are designed for our coloring often have red in them, so that they can be used by redheads as well. Since my hair is more on the ashy-blonde end of the spectrum, a brow shade with red in it looks just plain weird on my skin. I also love that Maybelline Define-A-Brow is an automatic pencil (no sharpening!) and it has a very fine, firm point that makes it a snap to get down in between my brow hairs. AND, this pencil lasts all day, even on my oily skin. I honestly don't know what I'd do if Maybelline ever discontinued this product--I depend on it more than any other product I own, to the point where I always keep a back-up on hand in case I unexpectedly run out.