I recently did all the research for my first AR, and it can get kinda overwhelming for a newbie. My conclusion was the Colt 6920 is the best bang for the buck out there. I got one for $957 shipped from dsgarms.com, which is pretty damn good (no tax either). Save up a couple hundred extra bucks.
The general consensus was colt, DD, or BCM is the only way to go if you plan on putting anything more than a couple hundred rounds through it. Buy once, cry once.