I'm a nicotine addict, but I easily get what I need in the form of my daily intace of nicotine. Not in the form of cancer sticks but what us scandis call "Snus". Shreded tobaco, either packed in a little teabag or in the loose form. Comes in different varieties and tastes. Excellent stuff but is however banned in most countries (which I guess makes it just as illegal as any other narcotic) except for in Sweden, Norway and Denmark (thanks for that EU).
http://en.wikipedia.org/wiki/Snus
Having a can of these in the crew bag usually alleviates any tension in the cockpit coming from not being able to go for a ciggy. It's a real icebreaker for those stressful days. The debate on weather it's healthy or not I'll leave aside as the answer is obvious.
Regards/ LnS