I gave up pop a while back. I never drank coffee so breaking the caffeine addiction wasn't too hard after the three day hump. Also, because I would normally drink pop in the evening I get better sleep and actually feel better/more energized than I did when I drank caffeine.

My thought behind quitting was that there was no reason to be caffeinating myself every day. That way when I do need extra energy hopefully my tolerance will be lower.