.22 LR is a great rifle to get for just going out and shooting.
It is also a hell of a survival round, although I would personally take .22 magnum over it for survival purposes
.22 LR ammo is cheap, which makes it less painful to go out and blow through a few hundred rounds. It is also a subsonic round, with plenty of great suppressor options for it. If you have gun shy neighbors, you can shoot it without any real sound pollution to bother them. I would get an conversion kit for an AR.
5.56 is decently cheep, although increasing rapidly due to the election. I don't like paying more than .40 a round for bulk 55gr or 62gr (XM193 and M855) surplus. It is a supersonic round, so even with a suppressor it is loud. You can build up a decent new AR15 for sub $800. Plus is that a conversion kit for .22LR makes that rifle cheap to shoot.
For defense purposes 5.56 will penetrate less than 9mm through drywall, wood, and people. The bullet needs to be traveling fast for desirable terminal ballistics in your prey be it 2 or 4 legged.
If you are looking for a good rifle for home defense purpose (get a fucking shotgun) I would look at .300 blackout. I don't really like to jump on bandwagon rounds, but this one looks like a keeper. Nice medium to short range ballistics. It is also subsonic, and you simply need a new barrel to make it work on your 5.56 AR15. It is more expensive though.
9mm is well 9mm. I would get it to shoot at paper and not a whole lot else. over penetrates, doesn't kill reliably... better than nothing I guess
.45 The only handgun round worth carrying. subsonic, so suppressible, and brings the hurt.