I have two 30-06's and three 308's, I like both calibers. If I had to choose one caliber for what you want to do, I would lean toward the 30-06. I have a Cooper model 52 in 30-06, that groups 1/2 in with 165 gr Hornadys and 4350. When it came time to pick a semi-custom rifle in any caliber I wanted, I picked the Cooper in 30-06 for the same reasons that has already been mentioned, versatile, accurate, ammo availability, etc.
You can't go wrong with a good 30-06 and good optics. I saw a friend of mine nail an antelope in Wyoming at 565 yards while it was quartering away, walking. He used an old pre-64 model 70 and a Zeiss 3x9 scope. I would have preferred more scope at that range, but it did the job. A few days later, I saw my friend nail a monster elk in Idaho with that same gun. I like that versatility! Good luck.