I quit smoking in February 2013. I'd been smoking since I was 12 and was up two packs a days for years - more when I drank... Best decision of my life.
I quit coffee 2 years ago - but started again when I started working daytime last summer. I used to drink a few pots a day, and couldn't function before my second cup in the morning. Now I only drink coffee at work on weekdays.
The one nasty habit I never managed to kick is soda pop - diet cola. I spent two weeks w/o when I was in the hospital last spring and couldn't wait to drink a diet Pepsi when I got out. That crap is highly addictive.
But one chooses his battles, and I have had other, more pressing battles than dropping soda pop.