Is caffeine healthy in moderation, or completely unhealthy?

I've read in some places that a cup or two of coffee helps fight skin cancer, contains lots of antioxidants, etc. so it should be consumed. But I've also read that all caffeine is unhealthy, so there must be some positives and some negatives. Does anyone have any info on these positives and negatives so that I can try to figure out whether one outweighs the other for my situation?