Cosmoline,
Great thread ... great enough for a sticky, IMO.
And a very nice choice for a first AR as well. As someone else mentioned, a nice KISS AR carbine is a great place to start. And with a lightweight barrel no less. That was my mistake when I purchased my first AR. 16" barrel, adjustable stock, full HBAR. Rifles like these aren't intended for all out accuracy, so though we do give up a hair of accuracy potential and steadiness with the pencil barrel, we gain so much in handling and speed. I eventually replaced my HBAR upper with a pencil barrel 1x7 flattop from BCM, and I've never looked back. In short, a HBAR on a fighting carbine doesn't make a lot of sense, unless you have a happy switch. But that is just my opinion.
And that is the beauty of the AR platform. The only limit seems to be how much room is in your safe and the size of your budget. And the "retro" ARs, oh my, they are a whole world unto themselves.
The 5.56x45mm is capable of taking any animal in North America with proper shot placement. Without proper shot placement, no caliber will take any animal. Don't underestimate the poodle-shooter.
People forget that the "lowly" 5.56 M193 ball cartridge was capable of inflicting some pretty horrific wounds inside 200 to 300 yards in Vietnam, do to violent yaw and fragmentation. I wish I still had the link, but there is evidence out there that the 5.56 M193 had greater wounding capability at
short range than the 7.62 NATO.