Florida.
1.) Remington 870P with 20" smoothbore rifle sighted barrel, RemChokes. I have this setup, and realistically, it can take any game in the southeast (really the whole eastern) US with ease.
2.) Marlin 925RM 22 mag bolt gun with iron sights and a fixed 4x scope. The bane of small game.
Really I can take any game with those in this area (close brush), so my last pick would be a pistol, probably be:
3.) a good old S&W model 29 .44 mag. Can take about any game with it from big game (to include deer and hogs) to small game (I got decent patterns with the CCI shot shells from my last M29).
Now, to come clean, I do most of my squirrel to rabbit hunting with the Marlin. I rarely hunt birds, and rarely use the 870 for hunting otherwise.
What do I hunt big game the most with?
Either a Mosin Nagant 91/30 or an AK (yes, as in 47), or I use a bow (recurve).
Now, to open up a different can: IMO, to cover ALL of your bases, you need 4 or 5 guns:
1.) Some kind of rimfire (pistol or rifle)
2.) Some kind of shotgun
3.) A good handgun
4.) A long(er) range/more powerful rifle
5.) A defensive rifle
If you pick a battle rifle like an M1, M1A, FAL, G3, etc, you can combine 4 and 5.