Bananas, bananas, bananas.

One bottle per hour or one bottle per 15 miles if it's REALLY hot out like yesterday. I went through 7 bottles through 75 miles yesterday (4 on a 30 mile mtb ride, 3 on a 45 mile fast road ride).

Energy gels are good, but take a Clif bar or two and some Clif energy bloks. You'll need something of substance, so bananas are great. They saved my but riding the mountains of Colorado earlier this year. Potassium will keep you from cramping.