One thing to keep in mind when deciding what to get, is to consider who your enemies are.
If you're in a bit American city like Los Angeles, you most probable threat are going to be gang-bangers who are probably going to be carrying a Glock 17 or 19, or other 9mm associated handguns. Go ahead and laugh at someone with a Hi-Point, just remember it'll still put holes in you. If you find yourself fighting the US or other NATO military forces (or domestic US Police), you're gonna have to worry about the 5.56 Green Tip; if you're a proud American and want to go fight the Russians in Ukraine, you're gonna be at the business end of 7.62x39. If your're a Californian and think you're gonna move to the mountains of Tennessee or Kentucky or West Virginia and don't like the mountain people who can trace their lineage back to the Mayflower, you're probably gonna contend with a WW2 Garand that shoots 30-06 and nothing will save you, they may have updated and shoot something in 300WIN, but you're still gonna get a large fucking hole blown through you. Kinda silly, but something to consider when you find yourself asking what to buy; know where your threat comes from and what they're most likely gonna carry. You (most likely) don't need Level IV while partying in Las Vegas.