1) Homosexuals. They engage in risky sexual behaior that results in a much higher rate of AIDS than the general populace. If smokers should compensate the state for medical services caused by their risky behavior then the same could be said for homos.
2) Tattoos/body-piercings. With Pamela Anderson admitting recently that she contracted hepatitis-C by sharing a tattoo needle with her husband, the public is becoming aware of the dangers of piercing the skin. The medical community is said to be gearing up for a 20% rise in hep-C caused by the latest tattoo/body-piercing craze. Hep-C is similar to AIDS in that it's incurable and eventually kills the host within 10-20 years. Again, if smokers should pay society for their risky behavior, so should those with tattoos and body-piercings.
Here's the discredited liberal ideal embraced by Democrats and libertarians:
"Allow me to be irresponsible, and I'll allow you all to pay for the consequences of my irresponsibility."