Ross, you've got numerous options.
Myself, I'm a build it myself kind of guy, but buying a complete AR isn't a bad idea either.
Sounds like WW has offered to help you out, and there's a good way to learn the rifle.
Beware of any funky fancy doo-dads like the changeable mag well. They may work OK, but you are going to end up losing some parts interchangeability.
Stick to the known names, and you'll be OK. Colt is good, generally high priced. Bushmaster and Rock River are better priced, and their products are good. LRB, Barrett, Les Baer and a few others make premium stuff. They are the quality they claim, for the most part, but, they are also higher priced.
The best suggestion I can make is to keep it simple, and go with an M16A2 clone (20" barrel) or an M4 series clone (16" barrel). Semi-auto, of course. Then, you can branch out from there, by swapping out a few parts to make it what you prefer.