None, usually. Having them "on display" in the rack in the truck invites thievery when I go to town, so I an usually empty. If going hunting, then the rifle / muzzleloader / longbow of choice- depending on season- is there. I am not a shotgun guy- never have been- I only own a few, and I do not hunt with them. I don't have anything against them, just personal preference.
If I am carrying and I need to go into a "no-gun area," I will lock it in the locking center console, or the lockbox in the bed. Usually, however, if I am going into such places, it is a planned trip, and I am unarmed the entire trip. I realize that it is not the best solution, but I would rather take my chances with my ability to run away than have a firearm of mine stolen and used in a crime.
I do have one hard and fast rule; The guns stay home if said "no-gun area" is a drinking establishment. If I plan to drink, I DON'T plan to carry. Even having one drink means impairment, and that is all a civil lawyer would need to roast me over a barrel. In even the most 'justified' of uses of a carry piece, the addition of an 'impaired' shooter casts a huge shadow of doubt over the whole thing. I do not take THAT chance. Bad guys, I can fight if need be... lawyers... I don't have the money to burn.