I don't even see a point in arguing, not that you guys are, and I'm not trying to start BS either. But both the .260 and .308 are great hunting rounds and either will do very well when used on the majority of North American game. There is not a ballistic table going that is going to disprove that, it has been proven over many years of use in the field. I personally feel that 600yds is pushing the limits of either round when hunting medium or large game. It's my opinion that if plans include 600yd shots on game, there are better suited rounds that will retain more energy, have less drift and will likely perform a bit better under a wider variety of conditions.
If shots were limited to 500yds with both on deer size game, 400yds on moose size game and maybe a little less on elk, you would have rounds that would be very reliable performers that would likely have no issue taking game cleanly. It's not that they won't reach farther, only that under adverse conditions it's often better to use a little extra at extreme ranges and a more powerful round would add a little insurance to ensure clean kills and may also provide a little "fudge factor" for errors in wind reading and other such errors with variables.
These are only my opinions, and I know others will feel differently and I'm sure some will say they can make longer shots with either round, and it's possible that they can. I simply feel these are sensible limits that will provide very good and reliable results with less chance of error.
Bottom line, either round will perform the task at hand, as will several others. There is no magic bullet diameter, no magic round. And when comparing 2 rounds so close in design and ballistic performance, it's hard to say there is a definite "better" round. Both have high points, both will work for the job. It really comes down to what you want to have in the magazine, a .308 caliber bullet or a .264.
I think the 7-08 would be a great compromise between the two and would be an excellent choice as well. But who am I to say what's right?
Kenny
edit:
I would just like to add that I do not have the skills or the confidence to take a shot longer than 300yds on a large game animal. I don't have enough practice shooting that far to be comfortable trying it on an animal. I also feel 300yds is plenty enough range in most situations to get the job done, and I honestly don't have the opportunities to shoot even that far when hunting locally, only when I travel out of my area. And even when I hunt elsewhere, I try to get into position where I don't need to shoot any farther than 300yds, that way I never have to push my skills when it risks a poor shot on an animal.