It depends on what you like. Some people like high tech energy replacers. I just eat food. Depending on availability I will eat bagels, peanut butter and jelly, fig newtons, apples, oranges, bananas, water melon, dried fruit, cookies, candy .... I think you get the idea. I know some people who can not handle any solid food on a ride and they eat energy drinks or GU.

Also it takes some planning. I don't need to eat if I am riding 50 miles. After 60 miles, I need something. On longer rides, it is best to eat before you are hungry at about 40 miles and about every 20 miles thereafter.