I have both the 7mm-08 and the .243.

I would disagree with most here, I find the .243 most useful, it can be used as a varmint gun and a deer cartridge. Although might be a little small for the large deer up in Canada, but fine for any deer in the US.

The 7mm-08 to me is the best DEER cartridge. Mild kick with enough power to drop them. I can't imagine what else you would really use the 7mm-08 for though... Pretty big for varmints and too mild for very large/dangerous game. Having said all that it is my favorite and go-to deer gun (Browning A-bolt and Remington model 7).