I was a heavy smoker 2-3 packs a day for years. I got my doc to prescribe Chantix and I quit in a month haven't had a cigarette in 15 years.
Although I still want one at times. There are times when a cup of seems to tell me "I would be a lot better with a Lucky Strike".
If there is a secret it is what my grandmother called "the wantitis" you have to want it really badly.
You know, I've heard good things about Chantix and Wellbutrin. I haven't taken them myself, so I can't say for sure. But I've known other people who've taken them who swear by them.