There are a ton of options for gels these days. Every nutrition company seems to have their own version of sweet, semi-viscous, gunk you can shoot into your mouth for a quick energy boost. Chocolate, strawberry espresso flavored, whatever you want. But, do you really want that in your mouth? My first encounter with gels was in the triathlon world. I'd take them while biking and running to maintain some level of energy while competing. On paper it seemed like a good plan, right up until I had to actually eat it. Now, I've used all of the gels from the biggest manufacturers, and in my experience, when you are at race pace, putting something like molasses in your mouth is not ideal. It would take multiple gulps of water just to get the thing down! It wasn't productive.
By chance I stumbled on Powerbar's gels (PowerGel) at REI and decided to try one. I was out on a ride when I took my first PowerGel and was immediately impressed. Not only was it viscous, it tasted great and went down without any water. Perfect. Since then, its all I've used. Sometimes I'll even take a bunch and mix them together in a gel flask for more convenient and regular delivery. For instance from miles 60 on, in 100 mile NUE mountain bike races, I'll try and take at least one PowerGel every hour.
There are a bunch of flavors to choose from, and some even come with caffeine! My favorites are the Strawberry Banana and Green Apple flavors. Check them out.