Will you be hunting only whitetails??? Which state??? What range do you usually shoot your deer??? If you are in a state where you aren't too concerned over grizzleys..and shots are within 300 yards...the 30-06 is more than enough gun...
If you want a gun to double as a deer/bear/elk/moose gun...the 30-06 is most likely still enough gun....I have several buddies that have 300 Mags stuck in their closets, here in NC that bought them "in case" they go out west...they don't ever shoot them because they are scared of them...I would bet more deer are lost each year due to flinching than being "under gunned"....Unless you are going to a state that has a good population of the larger grizzly/brown/polar bears the 30/06 will be plenty....If you are one of those guys that just has to have a 300 mag....go for it...
Just don't forget which closet you put it in later...LOL