I'm with everybody else that says:
1. Get a decent bolt rifle in something between .243 and .30-06. Caliber choice is really not that critical. Its far more important to have a decent rifle and be familiar with it.
2.Get a decent (at least mid-level) 3x9 scope and have it professionally mounted.
3. Buy a box of cheap winchester, remington or federal shells in the same bullet weight you'll be shooting at deer. That's usually going to be somewhere in the middle of the ranges of bullet weights available for the caliber of rifle you choose.
4. Sight your rifle in 2" high at 100 yards.
5. Then buy several boxes of ammunition from different manufacturers, you might want to also try some different bullet weights. Shoot them to see which gives you the best groups.
6. Go buy four or five more boxes of the ammunition that performs best in your rifle.
7. Shoot all but one box through your rifle in practice at different ranges. You'll know how to use and clean the rifle when you're done and you'll know where it hits when you do your job as shooter.
8. Show up in deer camp with something you have confidence in using, shooting and hitting with.
9. Standby for the quiet acceptance and appreciation that will be yours, and be thankful you didn't bring an AR that would make everybody else look funny at you.
added in edit: +1 to the guy who said buy and use a .22 a lot before you go. Rifle shooting and marksmanship =/= handgun shooting and marksmanship.