Only thing wrong with buying an AR-15 now is that well.. you are buying an AR-15
I'd avoid anything by hesse/vulcan/blackthorne.
If you only buy one, I'd avoid plastic/carbon fiber receivers and stuff. And I wouldn't put a bunch of tacticrap on it either. And budget an extra $200 or so for a 22 conversion kit and some extra mags for it. And start buying ammo now...