I want to add an AR-15 to my collection as my primary rifle. I thought about building to enjoy the process and get ma hands dirty. I have worked on AKs and SKSs but this would be my first AR. What would be some good companies to get my parts. I do not have my FFLs but I have a plenty of places near by to get the lower. Any advice would be great to start out with. I planned on a 16 inch barrel. The primary purpose is for  200-300 yards targets and some hunting. Thanks for any help.

Build!  I just started reading about AR's on here in the middle of the summer.  Built my lower and bought an assembled upper.  Easy as pie.  I would say that if you have the experience of working on firearms already you could buy some tools and build the upper too...  Welcome to the site enjoy your stay.  I got my stuff from eaglefirearms.net and Bravo Co.  There are many vendors on here that have exceptional customer service.  It really is hard to go wrong.  Click the industy tab to see who we have.  

Build, build, build.  

Personally, I would not use a 16" barrel for 200 to 300 yard tack driving, but that is just me.  I would either do 20" or 24" just to be able to reach out and touch something with great accuracy at that range!  Then again, to each his own, and if you want a 16", by all means build a 16".  You can build your 20" or 24" rifle next

Okay, you are going to get a ton of opinions from a ton of users, but here goes mine:

For the lower, I would either go with Stag, Mega, Double Star, or any other Military Spec lower that has a logo you can put up with for a decent price.  I must apologize to the Stag Fans because I still don't care much for the Deer Head on the lower.  With that said, I plan to purchase two Stag Lowers within the up and coming weeks, so I will just have to learn to live with it

For the Lower Parts Kit, you can either go with a Stag, any other (insert name here), OR get a kit that includes the Lower Receiver Parts.  I like the Armalite LPK that I just purchased, but that is just me.  The trigger is nice and crisp, the selector is sooooo very smooth, and the bolt catch coolest piece.  I can't say the same for the Double Star LPK because the last one I received was rough as hell and had a few bungled parts in it.

For the upper, I would definitely go with either a Stag for a complete one, or pick someone for a Kit (J & T Distributing comes to mind, but there are other kit companies out there if you search the web long enough).  Stag Arms has some very good prices on complete uppers, and you can sometimes find even better deals in the Equipment Exchange Section.  Look for a bargain, and you shall find one if you hold out long enough.  The only exception to bargain hunting is if you want a POF upper, which I want really bad.  They are too new and NOBODY wants to let go of theirs at a good price.

Stocks, up to you and depends on if you purchase a kit that includes one or not.

Optics, up to you (I like EOTech and Aimpoint, but that is just me).  For 200 to 300 yard work, I would go with something else, and I defer to the other AR15 members to help you here.

Sights, again up to you.  Plain old irons do it for me on one rifle, whereas optics sit upon the others.  Again, for 200 to 300 yards, optics would be a "must have" for me.

The best part about building is you get what you want the first time, rather than paying for a "stock" rifle, removing parts, adding parts, etc. which will end up costing you a lot more.  I made the mistake of purchasing a complete rifle some time back, and I could have built it WAY cheaper than it was to remove stock parts and add custom parts.  Building is not hard at all.  My former gun experience dealt with ripping apart every gun I ever owned and putting it back together again, then counting the leftover parts and calling a gunsmith (Just kidding about the leftovers and gunsmith because I only had to call a smith ONCE when I changed my plastic trigger guard on a Winchester shotgun to an aluminum one that took different parts all together).