I think your decision is sound.

For a first time high power rifle with a large venue of game to be taken, out of those cartridges listed I would go with you on the 30-06. Perhaps its a " jack of all trades and master of none" cartridge; however, in building an " early stages" rack of rifles a 30-06 is a darn good " anchor" .

If one owns a 22LR, a 30-06, and a 12 gauge, then you have a great start to a rack of firearms that will take you a long way.

Never Go Undergunned,
EKM