some 'experts' simply feel the negative effects of caffine outweigh the benefits. other 'experts' feel a little coffee is fine, especially now that they are finding new chemicals in there that seem to fight cholesterol and heart disease (much like dark beer, red wine).
all in moderation though.
as long as you're not currently suffering from high blood pressure or hyper tension, a little coffee is fine. Remember it can be a diuretic, so have an extra 8oz of water to counter that.