I'm gonna say a legit SPR with select fire capabilities and a suppressor (or no select fir if
just AR-15). Long enough to get some really good accuracy, short enough to get up close if need be. Accessories for it: Leupold Mark 4 4.5-15x50 scope w/ LaRue mount, Harris bi-pod, Surefire M951, some sort of Aimpoint/Eotech to throw on if it had to be used up close, and a semi trailer load of Black Hills 77 grain .223 ammo.
For some reason, I've been on a real kick to get one of these bad boys.
ETA, didn't see part 2
Part 2
OK I see if money wasn't an issue that high dollar, big name gets the nod.
NOW......
If money WAS an issue, and you can only have ONE AR, what would it be and what accessories would you buy ?
It would be the one I've got now. Mid-length carbine with a bolt on bottom rail, VFG, Surefire M951, collapsible stock and an Aimpoint (or fake aimpoint).