Batiste Dry Shampoo in Blush, $7.99
I barrel through dry shamps, and this one is my favorite. It smells fantastically powdery, drugstore-y and girly without stinking up the entire room. I use so much that it helps blend my roots with my ash-blonde highlights. It also permits me to wash my hair only 2-3 times a week so it doesn't get too dried out-- it's so long and healthy (mermaid length if you know what I mean).
I'd love it if someone bought me a case for Christmas because really, I buy a new bottle every two weeks. If you prefer a less powdery, sexier scent, I'm also a fan of their Diva dry shampoo -- the purple bottle has a disco balls and lasers theme (it's for party girls who don't wash their hair!) and is a cute addition to your vanity...in my opinion. OMG, and they have a Gold Shimmer version (for NYE, naturally).