Annapurna, 8,091 m, has the highest death rate, 32 deaths per 100 people successfully reaching the summit. That's a mountain. Everest is a comparative cakewalk.
I’m a purist. I like my mountains formed by a shift in tectonic plates. Volcanoes are just zits on the face of the earth
So how about we steal Olympus Mons and bring it back to Earth just to make all of these other answers wrong? It will be the greatest heist of all time.
No idea what NDT says it is, but I'd go Mauna Kea. Followed by Chimborazo. Strong contender for north pole on the basis if "north is up" though.