Cigarettes: filthy habit, glad I quit and I feel much better for it.
Alcohol: It's never been my thing. Drank when I partied but quickly realized the slippery slope and stopped drinking in excess. Now I have a beer or two at social gatherings and that's it.
Illegal Drugs: I enjoyed pot, felt great and had fun with my friends. I don't smoke that anymore either but mostly because I'm a parent and don't socialize with many people who still do. However if I'm at a party and someone passes a spliff then it's on.