Poll Results

Total votes: 3436

Mt Everest, Asia: 898 (26.1%)
Mt Kilimajaro, Africa: 677 (19.7%)
Vinson Massif, Antarctica: 637 (18.5%)
Mont Blanc, Europe: 409 (11.9%)
Mt Kosciuszko, Australia: 360 (10.5%)
Mt McKinley, North America: 337 (9.8%)
Cerro Aconcagua, South America: 118 (3.4%)

9 separate people went to the bother to hack in "Olympus Mons, Mars" as their answer.

The reason I asked this particular questions is because while this poll was running I was away on vacation, and actually climbed to the top of Mount Kosciuszko. You can read about what it was like in my travel diary.

One continent down, only 6 to go!