If you have truly decided that the M1A is "it", then get a used Springfield Armory Standard grade off one of the auction sites on the internet. What you care about is a GI bolt and a GI barrel. Any other commercial parts can be easily replaced later, but the GI bolt and barrel are mated, so replacement is problematic.
I don't care for any of the AR-style .308 rifles for a variety of reasons. Some people like them, though, so perhaps you will, too. IMHO, for most applications, the M1A is a better Battle Rifle, though.
Another alternative is to buy an M1 Garand from
www.odcmp.com. In this instance, a worn barrel is not too important, as you will send it off to be rebarreled in .308, thus using cheap .308 milsurp ammo. Cost of this alternative is about $800 or so, and is still a viable battle rifle.
Whatever rifle you get, buy Fred's Guide To Becoming A Rifleman from
www.fredsm14stocks.com, and learn how to shoot the thing properly.