I tend to disagree with everyone. I have 4 buddies that shoot 25-06s and they all blow up coyotes. Maybe thats ok with you, but I like to save my pelts an sell 'em. For that reason I'd stick to the 243.

As for optics.

Leupolds and Nikons are my favorites.

My Tikka carries a Leupold VXII 4-12x40 on it.

How much money you willing to spend on optics?