in some cultures they consume tea on a daily basis nonstop.. in some others they drink lots of black coffee.
caffeine isn't necessarily bad for you per se, however my view on it is simple.. its a drug, and its addictive. so if you want to be addicted to something forever then go ahead and drink it daily. starbucks and the coffee companies love that they have you whipped. also keep in mind how much sugar those starbucks drinks have and you might re-think your strategy.
bottom line is this.. I don't mess with caffeine very often.. if I need to stay up for a late night poker game I will drink black coffee or straight tea and take a couple atomic tabs.. no sugar or cream added. also when you start messing with caffeine often you will find it difficult to sleep, this is a huge problem in this game because we need lots of sleep for our muscles to recover! so a good rule is no caffeine after 2pm if you want to be in bed by 9 or 10! I dated a girl who had horrible insomnia and would stay up till 2am cause she couldn't sleep and needed to take cough syrup to fall asleep finally. guess what she drank 24/7? diet coke, which contains caffeine.. go figure.