Interesting thread and comments. One dear to my heart. The problem as I identify it is the average hunter, whom you guys seem to be addressing here, couldn't tell you how far any deer is at any range. Keeping it at 250 yds. is a good suggestion because modern "Mags" will shoot pretty much dead on like shooting down a pipe at that range. Just shoot the deer, no hold over and such. Unless the wind is howling, it wont matter either. However, under good conditions and with some understanding of your weapon, longer shots are not difficult with a nice firearm. I would encourage anyone to rangefind these shots in advance of seeing something to shoot, not just guess at it. Many of you mentioned shooting at extreme ranges but I know you will agree that looking over a meadow, a valley, and other vista's can be very deceiving. We practice at 300 and I know the gun out to 400 but you just have to think about the shot, your rest, the wind, even if you know the yardage to perfection(laser rangefinder). I missed one at 280 this year and I can only blame myself. Hell, I would love to say I never miss, but you know I would be lieing!
Bottom line, practice, be sure of the range beyond 300, and have all the other variables worked out before you squeeze the trigger.