To keep it simple, I would just go 223 Rem. 55gr SP's.
A $300 Leupold AR 3-9x40 optic with Nikon M223 mount or $200 Burris Fullfield II E1 reticle 2-7x35mm optic is good.
A carbon fiber tube or free floating Midwest Industries rails and a 16 inch barrel to keep it easy to move with is nice.
This way you can shoot close and not get too much magnification or do the standard calling and ambush approach as well.
I would stay away from any type of muzzle brake people are doing 3 gun with.
A standard A2 flash hider like in cherokee305's picture for a work gun is fine.
For an inexpensive trigger, look to Rock River National Match drop in for around $70.
For a $$$ $200 option, Geissele (guyslee) SSA-E or Timney AR10 #607 model is good.
A nice trigger really does complete an AR and helps in accuracy factors.
Magazines- Pmag 20 round models or 10 round models are what I like and work for me.
Magpul MOE pistol grip and stock are what I like also.
I stay away from bull barrels if I am wanting to keep an AR nice and light weight.
A VTAC adjusting 2 point sling is nice too if you will be doing some walking as it keeps your rifle cross slung in front of you or hands free to tension it around you.
The Jav's in my Avatar pic were taken with 55gr SP's and dropped them hard while going through brush on 1x where 4x was too much.
Sometimes you will jump animals and when you do, it is nice to have a low power optic to track fast.
It is all dependent on the terrain you will be hunting.
As you can see, kneeling with a 16" barrel, the barrel stays out of the dirt and the sling is a version of a VTAC sling.
If I was in open country, I would opt for an R15, adjusting stock, tube handguard, 18" barrel and 3-9x40mm Leupold AR optic.