I guess the 308 would be nice, but some of the big game rounds would certainly work as well. I will stick with the 223/243 for now because they are easier to tote in than my 7.62x54.
I should add, for the areas I have available to hunt, I really don't want any chance of bullet skip. Varmint rounds in the 223/243 are one of the reasons I go for these rounds. I am not sure if they have varmint rounds for 270/308 or not, but I would think it would be a good idea to use them if they are available.