If you have to give up one of the rifles, how much for the other one? Shouldn't ask that. Wrong forum.
Serously, the 30.06 might be 100 years old, but it has never been beaten as a flexible, do everything round. As important, you can always find ammuntion. Every little truckstop/bait shop in the country has 30.06 ammo behind the counter. I vote strongly for the 30.06