RE: Debating.....
7 Mag...An excellent deer cartridge. I have one that's a Weatherby Vanguard. Drops deer like lightning. Recoils more than the others. Shoots very flat. Ammo costs more than the others. Very loud. Ammo available almost everywhere.
30-06...Also an excellent deer cartridge. I have a Ruger 30-06. This too drops deer on the spot. Recoil is noticeable, but not severe. Flat trajectory out to 300 yds. Ammo is relatively inexpensive, and available everywhere.
270...I don't have one of these, but have seen them in action, first hand, on several occasions. Like the 7 Mag, is very loud. Has the flattest trajectory of the group. Drops deer on contact. Ammo is also relatively inexpensive and can be found everywhere. Great deer cartridge.
308..I have a BLR in 308 that is my favorite deer rifle. Drops deer like a ton of bricks with less recoil and noise than the others. Very flat out to 300 yds. Ammo is cheapest and found everywhere.
Bottom line on performance is: Deer will never know the difference, and inside of 300 yds. you never will either. Personally, I prefer the 308, but it is by no means any better than the others. Go after the best deal, best fitting rifle, and best looking rifle.
Good Luck