I shot my first antelope with a 243 @ 300yards in CO. In 2009 I shot my antelope at 327 yards, last year I used my 300wsm to shoot my bear at 138 yards on the run, my elk at 366 yards. Last year's antelope I shot at 257 Weatherby at 284 yards.
So for me it is choosing the caliber that I feel is appropriate and practicing with it. I couldn't get closer to the above mentioned game, when I can I do.
I think there are more people with opinions than those who actually are hunting and shooting. I wont take my 243 on my 3 bear hunts this year, or my elk hunt but if someone does so be it.