Sonic Drink Combos: Whats Your Poison?

I'm not a huge fan of Sonic. But where I live there isn't much choice. It's Sonic, or McDonalds. But one thing Sonic does that makes me a happy guy, is provide an endless variety of drinks. Not many people notice it, or even think about it, but you can add almost any flavor to any drink you want.

Recently I have discovered the glorious taste of Sprite with watermelon flavor. Holy dear it is delicious. But there are literally hundreds of different varieties you can go with. So, we ask you readers, when you hit Sonic, what flavors do you mix up to create the ultimate drink??