How about we members list our "Tried & True" gun/calibers for the animals we hunt?
Mine are as follows,
    DEER/GROUNDHOGS -- Win. M-70 Push Feed bolt, black fiberglass stock,
    Bushnell 3x9 scope in .30-06.  For the far shots !
    Ruger Redhawk S.S.  5 1/2" bbl .44 Mag for the closer ones.     

The Ruger is always with me no matter what I'm hunting though.
I use both guns for both animals.
   
My 13 yr son uses,
     DEER -- Win. M-94 Lever Action, Simmons 4x scope .30-30 
     .30-30 Win.    
     GROUNDHOGS -- New England Firearms Sportser Model blk fiberglass
     stock with a 3x9 Tasco scope in .22 Win Mag.
     S & W J-Frame M-642 2" S.S. .38 spl to finish off the wounded Hogs
     when we walk up to em'. (He always gets this job).

Nothin' fancy, but they work for us.

We all have our favorites, Caribou I like the 300 WSM with a 150 gr spire point. Deer is a hard one the M70 in 270 win with a 130 gr btsp is deadly but the S&W M29 with the 8 3/8" bbl is great 100 yd gun. Elk I`ve used my m70 in 338 Win Mag with 250 gr btsp. these worked well for me, bullet placement is everything, eastern coy dog the AR is good with 55gr sp as anything I`ve seen.

As mentioned before, BAR 338 Win Mag with a little custom work from Kevin Knight, A H&R 308 SB Ultra Hunter, and a Colt five five six.
We need some more catagories,
Scattergun: Benelli Super Sport #1 12 GA
Sidearm: 4-5/8" Ruger 3 screw .45, a case full of H110 topped of with a Freedom Arms Flat Point.
"Always behind the seat of the pickup" gun: Ruger Deerhunter 44 carbine (with half the bluing rubbed off because its always behind the seat of the pickup!)
Al

The worst one I`ve used to date was a 50 BEOWULF on an AR frame for deer was using 325gr hp little gun powder by Hodgon 1950 fps 3 shots clean through 1/2" holes bled like crazy still went 150 yds before dropping took out heart & lungs only hit short rib on the way out no other bone.

Elephant, buffalo 475 # Jeffrey double, lion 416, general plains game my 338 wild cat, bear & boar 450 Marlin or my 338 wildcat, deer 270 or 300 Jarrett, prairie dogs 223 in custom ARs.

Sidearm for finish, short shots, snakes 44, 45, 50 caliber depending on mood