I recently found Viso Vigor which is pretty good for a quick, intense (300mg) dose of caffeine. It also has tons of vitamin B (6, 12 etc.), and feels less to me like drinking death than Red Bull and the other canned energy drinks do. I don't drink it often, but if I need a boost that tastes good and isn't soda it works.

I also enjoy yerba mate. It's very popular in Uruguay where I started drinking it. Especially so among students as an (ostensibly) healthy herbal tea with a good dose of caffeine to keep them awake for studying. My favorite part is the slow, calming ritual around drinking it in the traditional way.

Those two exceptions aside, generally I prefer water.