I was just out picking up garbage for the 20-Minute Makeover, and not surprisingly, I would say >80% of the garbage was cigarette butts. I used to be a hardcore smoker and was once chastised by a stranger for tossing my butt on the street. At first I was appauled, but then I realized she was right, it is littering. So I started carrying around a mini M&M tube in my purse and would store my butts in there until I got to a garbage can. I'll admit it didn't smell the nicest, but it had a tight fitting lid and only really stunk when I opened it.
So I would ask those of you who smoke and maybe haven't thought about your butts as litter to try to be more earth conscience. Just roll the remaining tobacco with the heater out between your fingers (i.e. roll just above the heater). The charred tobacco will fall to the ground (which quickly decomposes and won't really stick around as waste) and toss the butt in a garbage can or hold onto until you can dispose of it properly. Film canisters work great too!