Not sure what the purpose really is..
if your going to shoot targets at a distance the smaller the caliber will keep your shooting costs down..
If you have a hand gun do a conceal carry permit for many reasons, mostly so you can transport it without going to the trouble of carrying it in your trunk and ammo elsewhere..
The added benefit is they are great courses for gun safety and the pros teach you how to shoot..
Most folks do not just target shoot, have a brother that uses a 22 and a 17 for hunting varmints on his ranch.. he loads the 17 with a LR high power 22 shell that has the 17 as the slug.. he is hitting ground squirrels at in excess of 300 yard.
The crows follow him when he goes out in the hunting truck.
If your thinking of hunting bigger game 30-06 is a super weapon.. Been around forever and you can reload the brass.
Hand guns again depending on what you want to do with them. from 22 to 45 caliber.
I keep a 45, Glock 9 and 380 in the house.. mainly practice with the 380 as the ammo is way cheaper than the 45..
Since I do not hunt or figure I'm going to be shooting anyone more than 35 feet away I do not have and long rifles anymore.. but do have a nice 12 gauge..
I figure that anyone coming into my house un announced, if they get past the 90 pound Weimaraner will not get past the 45 or 12 gauge..
My advise is going to gun shows and talk to the old farts that have guns.. See what they use them for and then study up on ammo and read all you can about the various brands.
Then go to a smaller gun store and trust the owner you may pay more for a gun but it will be well worth it when you have questions and I guarantee you will have questions, hard to get good answers from the snot nosed kid at walmart..
also make sure if there are kids in the house they take a gun safety class and get yourself a gun safe..
Since I have no kiddies around anymore not to worry..