For a basic revolver, a four or six inch barrel S&W K frame in .357 magnum. You could shoot .38 special in them too. For a high end revolver one of the Smith $ Wesson model 29 variants. I think 6 inches is about right for it.
For a basic shotgun, I would go for a Remington 870 pump or an 1187 auto. For a high end shotgun there is nothing wrong with any Browning over under be it superposed, Citori or one of the newer models. All of the shotguns should have interchageable chokes.
You forgot one of the most useful guns there is, the .22 rifle. The basic Ruger 1022 is not the best .22 rifle but it is perfect for a lot of uses and has so many accessories such a high capacity mags that it is almost a necessity.
I also think everyone should have a couple of high power European air rifles in 177 caliber. If it is really powerful it could be in 5mm or .22 . What ever you get stock up on ammo and accessories such as scopes spare mags etc.
I guess GMTA. While I don’t know how bad the economy may get under Obomber, I was going to recommend a quality pump or spring piston .177 rifle or pistol. They’re certainly cheap to operate, relatively silent, and extremely useful in supplementing the diet with squirrel, rabbit, groundhogs and fowl. If the utilities and sanitation services shut down they can also be quite handy for pest/rodent control.