I've used dope, automotive lacquers (with plasticizer), automotive enamels (prefer PPG), Hobbypoxy, Superpoxy and Klasskote. I think Klasskote gives great results, is easy to use (only one reducer), minimally toxic and has good shelf life. I've used a Binks auto touch-up gun for primer and base colors and a Paasche airbrush for trim work. I now own an HVLP gun which I will be trying soon.
My first choice would be Klasskote. If you have a desire to use more colors then probably acrylic enamel (PPG). If I were going to do a 'show finish' (like for Toledo) then I would probably go with acrylic enamel with a clear coat, but I doubt I'll be doing any more of those - at least until I move - my neighbors don't seem to like the smell of paint (especially acrylic enamel).
Proper ventilation is critical for your health as permanent liver damage can result from inhaling some types of paint vapors (Imron is quite toxic for example).
Nothing beats a nicely executed painted finish. Get a close look at the Japanese pattern ships - immaculate!
-Will B.