Started with a .44SPL Charter Arms "Bulldog" - about 5 years...
Then a .45ACP Star PD - also about 5 years...
Finally, a 9mm Glock 19 - 10+ years now and very happy with it.
I've also carried a small pocket-gun (or occasionally, early on, an ankle-gun
) as back-up to the primary or as a "better-than-no-gun" alternative for those times when the primary was impractical or impossible. That, too, has evolved over the years from a .25 Beretta 950 "Jetfire" to a .25 Beretta 21 "Bobcat" to a .32 Beretta 3032 "Tomcat" to a .32 Kel-Tec P-32 to, eventually, a .380 Kel-Tec P3AT with which I am very happy.
ETA: I just realized the initial post went beyond personal carry.
FTR, there is always a handgun, shotgun, and rifle in each vehicle (unless travelling where illegal, of course). As with
Charging_Handle, the addition of the permanent, vehicle-dedicated long guns was a
post-9/11 thing.