nice article.
here is also a theory why people who smoke cigarettes usually drink more coffee...nicotine induces an enzyme that is responsible for the metabolism of caffeine... I think it's CYP 1A2 if I remember right. Thus: more cigarettes, more active enzyme, less coffee/caffeine effect because it's eliminated faster... I noticed this when I stopped smoking. I never had a problem with drinking coffee in the evening (because I simply love the taste) but a few days after I stopped smoking, I had to skip that habit because I sat in my bed, eyes wide open at night :D