Coffee makes me PEE! One cup in the morning, and if I'm doing an early ride, I've got to get up early to get that cup with plenty of time to pee before the ride! :p
Just read this in the August issue of Bicycling:
"Reserve caffeinated gels or drinks for later in long training sesssions, because if you start with a stimulant early on, you won't be able to get a boost later in the ride when you really need one. Drink 6 to 8 ozs. of water when you eat a gel, and don't dilute sports drinks because when mixed as directed, they're specifically formulated for optimal absorption."