Yes, I've done a lot of stuff it my life that I'm happy about, but quiting smoking was far in away the best thing I've ever done.
The odd things about is this. I used to get sick about once every two years, though it took six plus months to get the chest congestion to go away afterwards. Now, I get sick 2-3 times a year, but the chest congestion only last about three months. (better, but still longer than it should take)
Within a month after I quit, I got a lung infection. It was extremely painful and felt like my lungs were collapsing. I couldn't move. I was stuck in the bed for about four straight days. The doctor said that it probably occurred because my lungs were in shock because there weren't being blasted with smoke anymore.
It took me about 10 years before I was able to successfully kick the habit. Anyway, as I said. It was be far the best thing I ever did, and I seriously doubt that will ever change.