I've got many of the calibers listed in this thread. However, if I didn't have a specific use for one; i.e. survival mode, but because of finances and/or a law that said I could only have 1; (Wives say so counts as a "LAW"), then I would go with the 7mm Remington Magnum. Between 110-180 bullets can reach anything from a rabbit to a moose. Short range deer and hogs to long range sheep and elk. There's not 1 thing in all of North America that it can't take.
This however is where the "What If's" come into play. If you live in Ohio or Pennsylvania and are primarily going to shoot those woods, then the 7mm rem mag might be a little difficult. However, with a small scope it would be fine. On the other hand, if you lived in Wyoming, Montana, or other Rocky Mt states, then a 30-06 would be really pressing your luck. Especially if the closest shot to an antelope or elk is 300 yards away.
So, it really does depend on your environment. If it was strictly a survival mode thing where you only had one rifle, then as mentioned earlier, I would choose the 30-30 in Marlin or Winchester. See through sites would allow short 50 yd shots with feeling comfortable out to 150 yards.
Of course, if I could have the two I listed, then there wouldn't be any question. A 30-30 and a 7mm rem mag together will literally do it all. Of course, a 22lr/mag and 12 guage pump would make everything complete.
308 and 30-06 are nice and have proven themselves over the years. That however doesn't make them automatically better. I love my 30-06. It has taken a lot of deer. But it has a lot of limitations compared to a 7mm rem mag. Anyway, my 2 cents. Later... Mike....