I tried drinking coffee before my commute. Once. Almost puked on the way in. Weird, eh? It just really upset my stomach.
It doesn't do too much for me, anyway. Wake-up or flavor-wise. I prefer triple shot mochas from Starbucks but they're freaking expensive, IMO.
I do have a 16oz can of "green" Monster every morning though. (Except when they were threatening to sue Rock Art Brewery!)