What an interesting topic!

Essentials:

For the heavy it will have to be a .500 3" NE double by William Evans on a screw-grip action with ejectors (because Andrew Hepner has one, I've shot it, and it's a hell of a gun).

Next up I'll have to pick my custom Brno 602 .375 H&H with a Leupold 1,75-6x in QD mounts. Plenty of buff, hippo, kudu, etc. over the years. Enough said.

For long range stuff a decent .300 H&H of sorts with a good scope and decent handloads.

Next up a good 7x57. I've shot a bunch of game with the calibre, from big wildebeest on down, and every good home needs one.

An accurate .223 with a VERY good scope on it, for when you really need to cull impala or shoot the odd jackal. They work well for the odd two-legged varmint in the full moon as well.

A best-quality Woodward "Automatic" 12-bore, 29-inch barrels, cased, simply because I have one and every good home needs one.

A Webley screw-grip actioned 12-bore with Southgate ejectors heavy proof, tight chokes and 70mm chambers. Waterfowl and see "Rule .223" above.

A .22 Mauser. Scoped.

A Browning Hi-Power 9mmP with plenty of mags, a shitload of ammo and a couple of decent holsters. See "Rule .223".

Must-haves:

My .318 WR dating from the early 1920's. It kills things DEAD and is just about the nicest calibre out there.

The A-Grade Oberndorf 9,3x62 I bought recently. Every good home needs one.

A decent .30-06. Worked for Ruark and Hemingway, a must-have to this day.

A decent AR/M-16 with plenty of mags and a REAL shitload of ammo. See "Rule .223".

My super-accurate Remington .243. Can't live without it.

My trusty Browning 12-bore OU. Can't live without it.