As a suggestion, if you're looking at an AR, here are a few things to ponder first. 1.) What is your intended use? 2.) Do you want a longer barrel, a heavy barrel, etc? 3.) What caliber do you want and finally, 4.) What mounting options do you want? (M-Lock, Pic Rail, etc, I think there's a third option now) Everything else you can pretty much chance on demand with one, but once you decide what you want, then you can narrow your selection down. I got lucky and picked up a Radical from Buds back early this year that has been good for me, but it doesn't get shot much, so I honestly don't know how much of a statement that is on it. You're basically buying a starter bundle probably, most of them you can switch out forearms, stocks, even uppers if you decide you want a different barrel later, different optics etc, skies the limit. Colt was considered the general benchmark I think by some. Ruger seems like they've got a decent reputation on theirs as far as I've seen, they even make a 20" heavy barreled free float one if you wanted something a little longer and heavy.
If you get one that's reliable and goes bang every time you pull the trigger, you can pretty much make it your own by the time your done...the ones that call them legos aren't really far off in that aspect. Side note, once you decide on the caliber, it may not hurt to go ahead and start stockpiling the mags for them while you still can. Everytime something happens in the world the supply dries up and the prices go up, so you're probably seeing them as cheap now as you're going to for awhile, and depending on the state you live in-the date you buy them on may very well decide whether having them makes you a felon or not.