Just embrace the evil dark side with the "Black Rifle" crowd.
They really are a lot of fun, shooting, building, customizing. They are like adult erector sets that go bang.
I would say buy a complete rifle first, less to worry about, more to enjoy. Lets you learn the platform easily, and if you buy a quality one, you can start building it up and modifying it to your needs or wants.
From there the real fun is doing complete builds. A good set of brass punches, and a few cheap specialized tools and you can build an AR in about an hour, and that's taking your time and checking it twice.
Then again I work with them and take them apart on a daily basis.
As for the scarf... I don't usually wear mine. As for looking side to side... I know people who practice it... I have been forced to practice it on a range a time or too. I know the purpose and the reason for it, I understand it, but I still don't normally practice it myself. There actually is theory behind it that is logical though, so it doesn't bother me when I see people do it.
I will say I stand up proudly as a huge Magpul fan. I use their products, enjoy their products, and very often recommend their products when building or modifying AR's for my customers. They are awesome to deal with too. Hands down the best mags for an AR are Pmags.
I know people will rag on me as a fanboy, but my current AR build I use the most looks like a Magpul product catalog.
The spec's on my current AR I use for defensive purposes, along with carbine courses, and range days at work:
-14.5'' BCM Mid Length Upper (I didn't build it, got a good deal on it)
-BCM Bolt Carrier Group.
-CMT lower and lower parts kit
-Troy Industries Drop In quad rail
-Falcon Ergo Grip in tan (this is my one non Magpul item, The ergo grip is slim, and is supper tacy rubber which is great for sweaty palms when running around)
-Magpul CTR stock in tan (awesome stock, sleek and rock solid)
-Magpul AFG II in tan (really is comfortable to me, but its not loved by everyone)
-Magpul XTM black/tan rail covers on side rails.
-Magpul rubber ladder style rail cover in tan on top rail
-Magpul MBUS rear flip up sight in tan
-Magpul BAD lever
-Magpul enhanced trigger guard.
-Magpul ASAP sling attachment plate
-Magpul Multi Mission Sling in tan
-Magpul Pmag x 10 in tan
-EOtech to top it off.
Had a tan Surefire Scout combat light mounted to it, but recently sold it to a buddy.
It is my current favorite black rifle.
You can tell I really drink Magpul koolaid.