LOL I logged on here just to do a quick search on the value of my 700 in .30-06. It was reworked by H&H in the 70's I think and i can't find any serial # info for range #21xxx.
In my experience there are usually way more offerings in appropriate hunting cartridges chambered in .30-06 available in most retails joints.
I have range time with lots of stuff- most recently my FAL in .308 - and the 700 in .30-06 would be the very last gun I'd sell. In fact I would probably disappear off the grid with it before I sold it for rent... or food for that matter.
You get a little flatter shooting rifle in .30-06, a few more choices in hunting ammo IMO and experience in most retail places, but the .308 should allow you to use the NATO 7.62 surplus which can be had for around .40 a round vs. $1 for .30-06 allowing maybe a little more range time.
In the end I'd start with the RIFLE you can get a GOOD DEAL on and one that fits you well and you like the looks and mechanics of and worry about calibers later on. Any .30 round is fine for just about anything that walks, crawls, gallops, (or swims for that matter) on this planet... I've seen Inuits kill whales with .30-06's....in the end shot placement beats the insurance policy of an extra 100 fps...
Depending on where you dream of hunting, sure a .30-.30 might not reach out far and flat enough, but in my experience most stuff from NJ to Namibia CAN be shot at under 200 yards, and with a few exceptions like sheep, antelope, and game under the jurisdiction of lazy guides usually is.
Find the perfect rifle for you and worry about caliber second.