The F-35 9mm38045.
Seriously, why limit it to a one size fits all? Two would cover it okay without too much compromise. You might want to get similar trigger pulls, i.e. not one single action and one DAO. An LCP II and a Glock 19 would cover all ground and are both striker fired, or substitute any two small/medium combos.
Most medium sized pistols work for IWB or OWB carry but carrying anything bigger than an LCP in a jeans pocket just doesn't work very well unless you cover that huge printing bulge with a shirttail or long jacket. Or wear jeans 2-3 sizes too big.
