Very nice response from jon', covers the bases. I would say, just from observation, that most people like the chilled drink better . . . but there are some who prefer it room temp. Gotta find what works for you. There are people who go straightaway for the higher-caffeine shots (I can't personally see any reason to down an 8-ounce drink instead of a 2-ounce shot, but, again, some people do -- I suspect that either they think, wrongly, that the bigger drink will have more caffeine, or that they just started with RedBull or Monster and it worked for them, and they don't want to change). But I think starting with the 5-Hour Energy is the way to go. There's a list here of caffeine levels in beverages: http://www.caffeineinformer.com/the-caffeine-database