Have you ever tried quitting smoking?

I know a lot of people are concerned about the affects smoking has on their health, others' heath and the environment. I thought it would be good to have a little thread about what other people have gone through when quitting smoking.

I quit about 3 years ago, and it took me about 2 years of trying to quit before it finally stuck. I would quit for a few days here, a week there, always getting pulled back into smoking by thinking I could take a few drags or smoke a cigarette before I learned.

How many of you have tried quitting smoking cigarettes, either successfully or unsuccessfully? What has worked for you?