Flint, but I'm not sure why. Maybe cause it's really all ya need. Maybe 'cause the nicest fowlers are usually in flint, although there are some really nice cap-lock smoothies too. I think there is a wider selection of smoothbores in flint, when you include all the muskets, but maybe not.
Maybe 'cause I've "gone flint", except for my minnie rifles. (although I keep having this weird fantasy of a 1863 or 1861 Springfield converted to flint...!!)
Maybe because since you have to get close up and personal to most things with a smoothie, the more "primitive" ignition of a flinter just seems to fit.
Rat