In real estate it's "Location, location, location". In guns it's "Application, application, application".
I like my '06 because I can handload up or down in power for any given bullet, and use bullets from 80 grains to 220 grains.
But if varmint hunting is the plan, it's my .243 or .223...
Because of the better relative velocities with bullets above 150 or 165 grains, I'll take the '06 over the .308. Again, because I handload.
The consensus from about 18 months of this forum seems to be that if you're skilled with whatever gun you use, a .308 will pretty much take any game animal the law allows. Why beat your shoulder to death becoming very skilled? That is, anything from .243 or .257 Roberts on up will work just fine...
I guess I'd recommend a bolt-action .22 and a whole bunch of off-hand shooting at beer cans at 100 yards. You'll figure out just how good you can get. THEN do some figuring about a "real" hunting gun.
FWIW, Art