I believe iced tea is no different then any other pop. It contains sugars and caffeine and in moderation I don't think it posses any problems.
As for Gatorade or its competitor Poweraid, these drinks are designed for a purpose to put back needed electrolytes back into your system when they have been depleted due to vigorous exercise. They probably pose no problem to the common person but would be nothing more then a pop type product if not used for its intended purpose. Probably slightly better then drinking an actual pop.
The Red Bull and products like this are designed to give you system an immediate jolt. These are best taken prior to a vigorous workout/exercise/sport but like most caffeine type products they wear off and for some people they crash. I also believe that the more you take of these there is a possibility of addiction or dependency but you don't receive the same results then somebody who takes in one in a blue moon.
I'm not a dietician or know everything and these are only my opinions from use and as well as seeing others. Heck, my wife is hooked on Diet Coke and cannot go a day without having at least one. If she does she gets headaches. I've seen this also with people and coffee in the morning and throughout the day.