It all depends on what you want it for. A bolt action .308 will give you more range. An M1A in .308 will give you more range and fire power. Still, a 30-30 lever action would make a handy general purpose rifle to have on hand.
Several people have also mention how nice it would be to have a .357 lever action because you could then shoot .38 or .357 in your rifle or pistol. That's not a bad idea and a .357 would be a handy carbine to have on hand as well. It would lack the power of a 30-30 though.
Again, it all depends on what you want to do with it.