I'm also new to the AR-15 owners world... I'm looking at the DoubleStar's. Aluminum construction, and all. For around $575. Or sometimes less on classified's. If you're on a strict budget, I suggest looking into them.
I love my Double Star!
I've had Colt snobs turn up their nose to my Double Star, but every time I ask them to specifically tell what makes theirs better- more durable- accurate... they get real quiet. My friend has a high-end, expensive Daniel's Defense... he pointed out to me that my Double Star had a better stock trigger, and that we both shot it more accurately than his Daniel's. I think DS is very under-rated, only because people aren't as familiar with them. When I get another AR, it will also be a DS. Love them!