Asking for personal opinions (not fact, logic, or proof) and expecting no debate seems unlikely.
------------------------------------
In general and personally my rule is, you can have " too much energy" for an elk or a deer and everything will still work out just fine -- no penalty for " excess" energy if the man or woman (Jessica Treu -- 416 Rem Mag) is a match to their rifle.

Too little, not enough energy for an elk or a deer and it becomes " hit and miss" with the better odds of success occuring if the rifle is in the hands of a seasoned hunter and sharp shooter. On the other (absent) side are unposted horror stories from the less experienced or less fortunate experienced hunters using insufficient or marginal energy that will NEVER fess up to what occurred that day.
--------------------------------
P.O Ackley was a wildcatter gunsmith and hunted world wide in the 1950' s -- he liked " light and fast" cartridges [notice that is NOT my mode]. One of is missions, kind of a morbid one at that, was to kill various animals worldwide with various calibers to determine the minimum cartridge/powder/bullet combinations for various game -- hence his treatise, " Killing Power." Per P.O. Ackley .....

There are three theories of killing power with mathematical backing - ALL are ammunition for argument and ALL have their falsities:
(1) Kinetic Energy - the easiest and the one favored by those who want a simplistic approach.
(2) Momentum - which has been proven repeatedly by Sharps Buffalo hunters and Safari Hunters.
(3) Shock Theory - (remember Roy Weatherby was fresh on the scene at this time) which favored P.O.' s wildcats, but a theory P.O. did not much believe in.
-----------------------------------
So to keep it " short" we are only talking about KINETIC ENERGY -- the easy one (Yeaaah). Humoring folks that need it easy, P.O. Ackley charted it out as follows:

Deer/Antelope/Sheep/Goat - AT STRIKING RANGE NOT AT THE MUZZLE:
900 ft/lbs minimum, 1200 ft/lbs adequate, 1500 ft/lbs or more preferred

Elk/Bear-Up To 600 lbs - AT STRIKING RANGE NOT AT THE MUZZLE:
1500 ft/lbs minimum, 2000 ft/lbs adequate, 2500 ft/lbs or more preferred

Large Bear/ Moose - AT STRIKING RANGE NOT AT THE MUZZLE:
2100 ft/lbs minimum, 2800 ft/lbs adequate, 3500 ft/lbs or more preferred

I guess I' ll go with the numbers from the guy that spent his life in the quest, and did it all rather than talk about it, and kept notes so it didn' t all become a " favorite caliber" blur.

[I' d rather be an " A" caliber student of hunting (preferred) not a " C+" (adequate) nor a " D-" (minimum). Heck use an extra 1000 ft/lbs energy and go for the A+!]
-----------------------------------

OH NO! You mean to have a COMPETENT discussion on killing power we are going to need to discuss at a MINIMUM:
1. Three or more different elements, of which " energy" is just one of them
2. Weigh the concept of " minimum" , " adequate" , and " preferred" (always absent in these posts).
3. Adjust energy to " what you have at impact" not " what you have at muzzle" (but, but, but what if I shoot at different ranges, hmmmm)

Damn, that just about ruins it for an online forum. Can' t we instead just take our favorite caliber (especially if it is the only one we have), jump up and down - declare it the best and dismiss everyone else -- its a lot more fun that way and doesn' t require any thought, logic or proof/reference.

How could an old coot from the 50' s get so in depth and complicated on this seemingly simple subject and he didn' t even have a computer. Maybe if he would have had his own web site instead of a book he would have " dumbed it up" a bit for Internet consumption. Hey, I' m a 21st century man -- I want it whipped up simple, colorful, and easy with something I can just " click" on -- never mind understanding it, I want entertainment value.
-----------------------------------

Oh, well -- at least the animals are the same as in 1950.
Just, match your tools to the job at hand, and of course....

Never Go Undergunned
EKM