I am soon to be in the market for a new rifle. My firearms collection currently consists mostly of hunting rifles (from .22 to 300 Weatherby Mag), upland game shotguns (12 and 20ga double barrels), and a wide range of pistols plus a Remington 870 12ga for basic home defense.

I have never been into the military style assault rifles and there are a huge number out there and I am hoping someone has some advice to narrow down my research. While I do plan on shooting this for fun, I also would like to have it available for WTSHTF situations.

Requirements:
.223 or .308 caliber
highly reliable under field conditions
Relatively low weight (would be carrying with a BOB+)
Easily field maintainable

Cost is not really an issue as long as it is less than 2-3K. I'd much prefer to spend more and have a more reliable gun. Please be as specific as you can as I know there can be a large variance in quality between manufacturers and even years of manufacture.