C. G. P. Grey:
In order to be more informed, I went off to do some research. The short answer is that back in the 1980s a few studies of caffeine came back with negative health results. These studies were widely republished and started a backlash against coffee but have since been disproven.
Caffeine is one of the most studied drugs ever and there are essentially no health problems for normal people ingesting normal amounts of the stuff. And, aside from that, the benefits that it provides are real and measurable.