Congrats tekoken!!!! I too jumped on the AR "love boat" late, so much so, that my first was a Sig556.

Cause it wasn't an AR....only similarities were mags and ammo. I finally built my first AR, and enjoy it immensely, and am also considering a .300 upper.
So you went the .300 route. That's good. Very much mo' betta multi purpose caliber.

However, for your consideration, see if Santa can find a way to get you a plain ol' 5.56/.223 complete upper. DPMS, Rock River, Stag, etc,.. nice and simple. Here's why:
IMHO.
1) Ammo is cheaper than the .300
2) Mags and bolt carrier group, charging handle all stay the same. Just the barrel is different.
3) There will always be .223/5.56 ammo more easily attainable than .300. (good to stock up). Considering a possible BHO re-election, would be good to keep the .300 rds. for a "rainy day"....
4) Price per rd. adds up at the range for plinking/range time.
5) Changing uppers takes about 10 seconds. Including a coffee break.

6) Did I mention .223 ammo is cheaper?

As far as accessories, it's a personal thing. Some like vertical fore grips, some don't. Some like lights and lasers, some don't. The AR's are like "Barbie" for gun lovers, you can put as much or as little as what suits your particular taste and application.
Please keep us posted with pics and a range report. Daniel Defense makes top tier stuff. I have one of their flat top uppers on my AR.
Good shooting!!!
tw