My worst death... comes from being over-confident after playing for so long.
I had been on a gate-closing spree, like you do. I do different things in different gates to amuse myself, in this case, although I'd battled a few rooms of enemies, I decided just to sprint for the Sigil stone and not bother with the high ranking dremora nearby. I misjudged either close he was and got knocked down before I could get to the stone. My toon gets up, backs up a bit... aaaaand, I am focusing on one enemy, not noticing a second guy had made it up there - I get hit from both sides and I had moved too close to the edge of the platform- I went flying into the pillar of flame. which is like 10K hit points.
I may still have a screenshot somewhere.