The best DOS Shooters were
Blood 
(great, creative level design and definetely the coolest weapons)
Heretic (besides magic wands you also head magic spells; great sound and sound effects)
Hexen (you could choose between different characters, as in heretic you head weapons and spells, and levels were non-linear).
I couldnt choose between them, but each of those beats all the others mentioned in this thread.
PS yes, in the above poll it would be Wolfenstein3D.
