I've got extinguishers in a number of places around our house. Each floor has a decent sized ABC - Dry Chemical extinguisher. In our kitchen, there are three cmaller extinguishers and an ABC in the adjoining pantry.

I'd like to pick up a couple decent sized CO2 extinguishers. I know CO2 is not the ideal material with which to try to put out a Class A, but it can work. It is much better suited for putting out Class B or C fires. If you have a pure Class C, CO2 is probably the best type of extinguisher, IMHO. I'd like to put the CO2 extinguishers near my main electrical panels and outside the mechanincal space in my basement.

I've used dry chemical to put out a fire, and it is a nasty mess, as mentioned by Art_in_FL.

It's important to note that there are other methods by which fires can be put out, and sometimes those methods are better. If you have a flaming pot on the stove, a pot lid the fits well should do a great job. If you have a small class A, why not a little water, if something to apply it is conveniently close.

We need to always remember fire requires fuel, oxygen, usually some heat to change the fuel into vapors (only vapors burn) and no interruptions to the chemical reaction of burning. Dry chemical hits that last part. But remove any one of them, and out goes the fire.