I would lean toward a Ruger 10/22 in Poly/Stainless or Mossberg pump shotgun as an "only" long gun. But after that, for a general rifle, the vz.58 still fits most user criteria in regards to accuracy, ammo availability, dependability, and price.
I agree with everything CP posted, with one exception. The pump shotgun. They're hard to master manipulation under stress (including very necessary tactical reloads with limited capacity), limited capacity, limited effective range, have a mean kick, and while they do have a very versatile ammo selection -- the 12 or 20 ga shotshell (add 16 if you want, but those are the only 3 gauges suitable to general purpose; .410 is not) is extremely heavy, bulky, and inefficient relative to centerfire or even rimfire rifle cartridges...
I can think of 5 scenarios where I'd prefer a shotgun over a 22lr rifle:
-3 or fewer human threats within 25 yards
-Hunting birds in flight
-Hunting or defending from larger than deer-sized game, including hogs, bears, etc, slugs for all and preferably with a rifled shotgun...
-Dealing with a crazed, drugged, or otherwise out of normal consciousness human whom you quite literally have to bleed out, stop CNS function to stop the aggressor -- most humans have a sense of self-preservation where 22lr, including multiple shots, is adequate
-Lastly, the paranormal, including fast zombies and vampires -- the former due to lightning fast speed being like birds in flight and the latter as silver is much easier to load into a shotshell combined with aforementioned (potential) vampire speed...
I also cannot state enough the value of having a 22lr pistol for new shooters as well... Starting there helps develop good habits rather than starting with larger caliber, learning bad compensating habits, and then having to unlearn all of those bad habits to become a good shooter...
So 22lr rifle + 22lr pistol is a pretty great foundation combo for anyone's firearm evolution. And I don't think 22lr is nearly as inadequate as some like to state, but it's also not ideal either...
CZ makes some great 22lr rifles too if you want an accurate, classic wood long arm. 22lr pistols, I'm partial to Bersa, but Rugers are good too (though much more difficult to disassemble for regular clean but do digest a wider variety of ammo). Beretta has some good 22lr pistols too but mags are difficult and expensive to obtain and have less capacity than the Bersas.
*EDIT: And a clarification -- WASRs are reliable/go bang in stock configuration, but their build quality varies quite a bit, so probably not a "great" rifle for your average WASR. Not too much different than the Century monkey reputation, except that their rifles work... Rifle dyanmics did have a basic WASR upgrade package for ~$300 that tuned them up considerably (Bolton block and barrel shortening and upgrading furniture were extra $ above $300), but don't see it listed on their website currently. You can read about it here:
https://www.shootingillustrated.com/articles/2012/1/31/rifle-dynamics-fine-tunes-the-wasr-10/They are also the most common AK variant in the states, which is a probably good thing...
