Voted for

• Milk
• Juice
• Water

If I drink anything at all right after I wake up, it's water, and that's generally to help clear my throat as much as anything else. I'm not sure if it's helping me to wake up or become more alert.

Once in a while, I'll have juice first thing, but since I don't normally eat breakfast immediately after waking up, I'll wait to drink the juice with the meal. I'm as likely to have milk in my cereal, though, as I am to drink juice.