Summary
A (probably imprecise) summary of the results so far:
22 votes:
21 votes:
16 votes:
- Red Hand of Doom
- Keep on the Borderlands (B2)
12 votes:
- Tomb of Horrors
- The Lost City (B4)
11 votes:
- Sinister Secret of Salt Marsh (U1)
- Castle Amber (X2)
- Isle of Dread (X1)
9 votes:
- Age of Worms
- Lost Caverns of Tsojcanth
- Desert of Desolation (I3-5)
5-8 votes:
GDQ1-6, Against the Cult of the Reptile God, The Banewarrens, Dead Gods, Return to the Tomb of Horrors, Rappan Athuk, Return to the Temple of Elemental Evil, The Gates of Firestorm Peak, Expedition to the Barrier Peaks, Slavers, Dark Tower, Night Below, Burnt Offerings, Shackled City, White Plume Mountain, Caverns of Thracia
I don't feel qualified to nominate the 5 best adventures, but my honourable mentions would go to Desert of Desolation, The Freeport Trilogy, A Paladin in Hell.