Anyone of the 7mm variants(7mm-08, 7mm Mag, 7mm WSM) will do the job but the 7mm Ultra Mag is overkill unless you are going for big game(Elk etc.)
I use a 7mm Short Action Ultra Mag, great rifle but unfortunately it lost the caliber war with the WSM cartridges and now the ammunition is hard to find.
I would rank the 7mm bullet up there with the .30cal for versatility of bullet weights/construction. Everything from 120 grain V-max to 200 grain Bonded big game type bullets are availible.
Try sticking with one of the tried and true calibers for a general purpose rifle: .270, .30-06, .243, .308, 7mm, 6mm
Or if you want to have a odd ball caliber but equally effective rifle try these: .257 Roberts, .25-06, 8mm Mauser, .280 Remington. This odd ball selection could go on forever.
The only cartridge I would not recommend is the .30-30 soley on the basis that the ballistics suck after 200yds. I used one for quite a few years and harvested multiple deer.
Just my two pennies on the subject
