Coffee-based drinks have too much caffeine in them for my liking.
Energy shots are good only when you know you're not going to be able to sleep for more than 24-hours, and take one at the crashing point to keep going. They are extremely effective, far more than anything else in this category, but not healthy for you at all.
Basic energy drinks I really like, in their sugar-free form. I'm fairly resistant to their effects, but they wake me up just a little bit and have no negative side effects I've noticed, only positive, and depending on your location there's always a brand that can be gotten for dead cheap. More than one can a day is not recommended though.