Thanks for the post, and the replies. This had been a question of mine for some time as well. I have (some months ago) determined that .308 is a better choice, for a number of reasons.
1- Being a widely used military round, ammo is relatively cheap and easy to come by.
2- I am not a precision long-distance marksman. If I ever do become one, I may revisit this question, but until then, .308 is more than accurate enough for my needs.
3- I would also plan to use said rifle as a hunting rifle. It would be unwise/unnecessary to get something I am going to blow away at realistic hunting ranges.
Just my two cents.