As far as long guns go, it depends on where and what you may want to hunt. IMHO to cover anything in North America I would suggest:
1) a good .22 rifle
2) a 12 ga. pump shotgun with multiple choke tubes and a second rifled slug barrel
3) an AR-15 in .223
4) a good .30-06 rifle
5) a .375 Ruger or .375 H&H rifle
If you never plan on going after moose or big bears, you could eliminate the .375. If the biggest thing you ever go after are deer, you could substitute the .30-06 for a 7mm-08. Yeah, I know some hunt elk with 7mm-08, but I want a little bigger gun, just my preference. With the above "battery" one would be well armed for anything on this continent or the planet, for that matter.
