In reply to Ian Hill:
I think doing the Big E with O is kind of cheating. Big E is 29K feet high and the Oxygen at that height is of a certain density and richness (or lack thereof). If you want to say that you climbed Big E, then you have to be able to climb breathing the O at that height. Otherwise, you climbed something lower. If using O, you have to qualify your statement that you "climbed Everest using bottled Oxygen". You can still claim that you climbed it, but you need to say "with Oxygen".
Some of you out there may argue along a similar line that the air temperature at 29K feet is so many degrees F or C so if you wear a down suit climbing Everest, you are cheating. I don't think it's the same argument. You die up there if you don't have adequate insulation; everybody does, bar none. But not everybody dies climbing without O so I think it's different.
Similarly I don't think it's cheating to wear crampons climbing Everest. Without those, you won't be able to make it up there. But Oxygen, Messner and Habeler proved first that you can get up there without.