OK, I'd love to see the firearms thread restarted following this format:

Here's a few weapons that I see as interesting & useful for survival situations:

The AR-7
.22 Caliber

Good things: It's exceedingly light, it's fairly accurate (under 50 yards) and it's got some of the coolest packaging - the whole gun breaks down and packs in it's stock, which floats. It fits in nearly any backpack.

Bad things: Early versions of the gun from charter arms and others have a disturbing flaw that can allow it to go "full auto" on you. Not a good thing when you are conserving ammo. Although the current version from Henry (US Survival Rifle) clears this problem up, like the original, it can't handle hypervelocity ammo like the Stinger or Velocitor.
What would make this gun better: A .17 HMR version might be nice.

The Winchester Model 94
Caliber 30-30

Good things: A time-tested compact lever-action gun (mine was my grandfathers) that reliably fires a big, slow, clumsy bullet that can kill many animals and will slow down many others. 30-30 ammo is widely availible, as are parts for the gun.

Bad things: Not exactly a "lightweight" gun, and the ammo is freakin' heavy to lug around too. Useless for birds and a bit much for very small game you intend to eat.

The Mossberg 500
12 or 20 Gauge, 18" Barrel

Good things: A light, reliable gun, which, like all shotguns, offers a wide range of ammo options from light birdshot to rifled slugs. I find the Mossberg to be a more "intuitive" gun in terms of position of the safety compared to the Remington 870.

Bad Things: It's a little "sloppy" in construction, and the finish on mine was a little rough. Of course, shot shells are big, heavy and all that.