Lots of us local boys roll our own ARs. I can help and I'm sure others will offer too.
First tip - do NOT buy anything until you have a chance to try some of ours. There really are a lot of choices. Within the GA gang, I think we've got all the variations (and then some) covered.
That said, what do you primarily want to do with the rifle? Matches? Home defense? Plinking? Target shooting? Kill the zombie horde when they march on Dallas? Scare the neighbors? Hunting?
Of course, we all know the answer is ALL of the above!
Of the top of my head I suggest a 16" chrome-lined barrel in either a mid-length or carbine length (this refers to the length of the gas tube; barrels are still 16" on both systems). The upper should be a flat top, which offers more versatility. Skip the removable carry handle. Buy a good BUIS (Back Up Iron Sight) for the same or less money.
Stick with a good name brand. Right now I think Rock River Arms is the best bang for the buck. Other choices include Buchmaster, Colt and Armalite.
Welcome!