SF troops have given 6.8 round great reviews. AR-15 6.8 upper in very cost effective, uses same mags. You get two rifles in one.
Were I starting my collection, I would probably go for the M1A. I don't think that any of the others are any better overall, and remember, you are planning to buy the rest anyway.
ping for later
Springfield Armory M1A:
Synthetic stock, standard model. Shoots almost like custom (well within MOA if you do your part) -- Reliable.
Google: SAGE M1A Scout Squad EBR
I had two AR-15's for years but recently sold them and bought a Springfield Arms M1A which is totally sweet. It's a lot heavier but the 7.62 round screams.I never liked the sound the buffer spring makes in the AR-15's it always made me think the thing was going to fly apart. I figured since I was re-loading .308 for my Steyr Pro-Hunter I would rather have everything in one caliber.
Thread Reloaded...
How is your (Mulder and everyone else) battle rifle experience 18 years later?