I usually start by picking a cartridge first, then see what's available from the manufacturers - and the "which cartridge is better" pissing matches just annoy
me. As stated by so many others, if you don't reload then the 30-06 is the way to go. Then should you decide to get into reloading, the 30 cal has by far the
largest selection of bullet weights and types of any caliber. If you do reload, then you already know this. Should you choose the 30-06, then you will definitely
have the largest selection if rifles available to you, so you would then have the unenviable task of visiting the various gun shops to look at and handle all the
rifles that interest you to see what suits you best - oh you poor bugger, you really do have my sympathy.

As for which make and model you should
choose: If it feels good, do it.

As for the cartridge, like so many before me have stated: "They all put holes in things", it's the adjustment of the nut behind
the trigger that determines if the hole is in the right spot. Enjoy the hunt.