No question about it, i would get a Remington model seven in .260. Its a gun he will always be proud to own and in a caliber that he will never outgrow. He can use it for deer, elk, sheep, mulies...whatever. It will fit him now, and in thirty years when his son shoots it, and he buys one for him.
Did i mention that a .260 doesn't kick much more than a .243, but will do all that needs doing for non dangerous game? A 7mm-08 is another choice that IMHO would be equally qualified.
Crap...now i have to have a seven in 260 for myself!