Didn't you do this a little while back?
Personally used and favorite would be .270 Winchester. However I don't consider it a "perfect" elk cartridge even though IMO it is a very good one and better than most people give it credit for.
Of course after this upcoming season, keeping my fingers crossed I'll be able to get out there, I will probably tell you my .338 ultra mag is my favorite.
I know this isn't part of the poll but I think the one best suited to the largest number of people would be the 30-06.