This was a really tough decision for me, they all sound so delicious and pleasing. Though, if I had to choose only one, it'd be Coca Cola, for the taste and fair caffeine dosage, along with having slightly less sugar than Pepsi, Sometimes I find Pepsi to be a bit too sweet. Second choice would be Sierra Mist, but it can't be in the aluminum can. For some reason, the bottled versions taste much better to me.