Stag. Lower, LPK, upper, stock, and buffer are Stag Arms. It's really nothing too special, but it's reliable. I'm not sure why Stag gets a bad rap. The only issue I had with it was some upper/lower pin fitting, but after that, all it needed was lube and the occasional cleaning. I cycled about 500 rounds of wolf through it (only 500 because it's useless for anything but short range plinking), and it stank, but it cleaned up just fine. I had some issues with feeding initially, but those disappeared when I broke it in and/or learned how to lube it properly. It has been smooth and accurate, and I'd buy another in a heartbeat. The carry handle sight holds a zero nicely, no matter how many times I remove and replace it.
Handguard. The Magpul MOE Handguard was the only purchase that was made only for aesthetic reasons, but it turns out that it's actually a better fit for my small hands. Since it's easier for me to get a grip around the smaller handguard than around the standard handguard, I've noticed more recoil control, and better general control when holding the rifle by the handguard.
Zero. It's zeroed for 200 yards with the Improved Battlesight Zero. I'm waiting until I can get some better distance estimation before I zero it back to 300 yards. I've considered a thinner sight post because I really like them, but I'm going to wait to make sure it would improve my shooting. If it ain't broke, and all that...
Flash Hider. It's fitted with a Vortex flash hider, which virtually eliminates muzzle flash, especially under semi-automatic fire. While flash elimination is technically useful, it really doesn't apply to defense shooting, so it's really just a neato purchase. But the best thing about it is that it rings like a tuning fork when the bolt closes. Just a little bit more character for the rifle. :)
Left. The Stag lefty upper is due to my cross dominance. Interestingly enough, I shoot more accurate single shots left handed, but more accurate rapid fire right handed. Despite being a lefty upper, I don't have any problems shooting right handed. I also haven't had any complaints from other people who have shot it right handed. Because the upper is the only part that is left handed, I've worked out different ways to operate the mag release (on the AR that isn't mag-locked), and can reach the bolt release with my left middle finger, but I have to break my grip to do it.
Stock. A Stag Arms 8 position stock with a zip tie around the back of the stock to attach the small clip of a sling that won't around the thick loops for a sling to run through. Just more mounting points.
Beard Saver. There is a crocheted wrap around the beginning of the stock to keep errant beard hairs from becoming pinched between the stock and buffer tube. When this happens, beard hairs are yanked out, much to the shooter's annoyance. You can decrease the chance of this by getting a stock that fits the buffer tube better, or you can eliminate it by buying something like the Magpul UBR. Or you can just spend a few fractions of a cent on a short length of camo yarn, and do what I've done. No beard hairs have been lost since then. Some electrical tape has also been placed over a hole in the top of the stock which, much less commonly, was known to pull beard hairs.
Grip. Inside that Magpul MOE grip is a complete replacement (lefty) bolt, and a field repair kit of spare parts. Aside from storage, the grip also improves on the original ergonomics in a number of ways. It's thicker, which allows for a stronger grip because it fits my hand better. It's at less of an angle, which gives my wrist a more natural, and therefore more comfortable and stronger, position. Finally, the new backstrap repositions the web of my hand so that the trigger pull is more straight back. All these things mean more comfort in shooting, and more strength in one-handed holding. I bought it for the storage, but the ergonomics were a pleasant surprise.
Safety. I use an ambi-safety because I find it easier to operate from both sides. Using my thumb to push it down into the firing position, and the first joint on my trigger finger to drag the lever back to safe. I have small hands, and I don't know if you're supposed to be able to flip the lever to safe with your thumb, but I can't, and this is what works. With practice, it's very smooth to go back and forth without compromising your grip.
Lock. California legal ARs must be in one of two configurations. This configuration includes "evil" features (pernicious pistol grip, atrocious adjustable stock, and foul flash hider!) so it must have a magazine of a capacity no greater than 10, and that magazine must require a tool to remove. I've used a Bushmaster mag lock (the silver nut where the mag release should be) with a Bushmaster 20 round magazine body that's blocked to only take 10. At first I was bothered by only having 10 rounds in a defense weapon, but I realized that I could do more with 10 rounds in this rifle than I could with more rounds in any other gun.
Sling Mount. At the base of the buffer tube is a Vltor ambidextrous single point sling mount. It's set for lefty right now, and I like the single ring instead of two rings on both sides. I may replace it with one of those new slider mounts that lets the mount clip slide from left to right, but it's not to difficult to hold it right handed in the same mount. I like the idea of single point slings for some situations, but I've tried to keep as many slinging options open as possible.
But all that is just half of what makes this my rifle. The other half is me.
Me. I can't say that I have shot my rifle until the pins walked out and the handguard grooves wore smooth, it only has about 1500 rounds through it. But I've tried to learn from each one of those rounds. I have no interest in making noise and flash, I want my rifle to be an extension of my will. Live fire practice was only a part of the training. In fact, for every real bullet I've shot, I've probably shot three imaginary ones. Practicing shooting "O"s on the teevee with my unloaded rifle has grown the rifle to my shoulder, the stock to my cheek, and the sights to my eyes. As I've said before;
You will be amazed when spotting a target, snapping your rifle to your shoulder, lining the sights on your target, and achieving a motionless trigger break comes as naturally as reaching your hand out, and catching a ball in the air.
I'm not sure the rifle is a complete extension of my will just yet, but it's damn close. I look forward to that day, and will continue to work toward it.