Tough one to answer without knowing what kind of stuff you already have.
Everyone should have a garand-but two CMPs? I would get one & maybe a Springfield .45 Mil spec that'd make a fun pair of guns.
The Eagle arms AR-10 is a tiny bit under $ 1k, but mags are expensive-I'd choose the DSAFAL first-altho my choice would be a clean SAR-8 (?) or whatever the Springfield armory copy of the HK 91 was, they are under a grand, I think, and will take cheapo Cetme mags. The lowest end Springfield armory M1A's are also a tad under 1k and mags are cheaper than an AR-10.
The smallest Kimber 45-the ultra CDP maybe-is around a grand and comes with night sights and a cool looking "melt" job, altho I would find one with the older safety, not the new System II or whatever it is called. But those are VERY nice looking little .45's.