Alcohol should never be used for fire breathing because it is explosive and in some cases may cause poisoning or drunkenness (as demonstrated below).
If one was to attempt to breathe fire, the recommended fuel would be kerosene (or paraffin if your fire breathing internationally) because it has a relatively low flash point (the temperature at which the fuel ignites). Personally, I would not attempt to breathe fire myself - the thought of swallowing flammable liquid and spitting it into a flame a few feet from my face doesn't seem enjoyable.
Happy Fourth of July! Yes, I know it's the fifth, but I was far away up in the mountains unable to post any independence greetings.
I witnessed a firework mishap this weekend, a reminder that fireworks are not toys, and should not be handled by children, drunkards, or in this case, people with bad luck (no one was hurt, badly).