Personally I like great villains, Thanos, Doom, Doc Ock, Joker.... but thats jut me, on the list there, yes, Superman is the classic hero, the epitome of heroics, so he would probably be the most popular, although I think Batman, Wolverine and Spiderman appeal a great deal to people in this day and age, and would be very close to the top spot...especially with the movie sucesses of X-Men and Spiderman putting them out to a wider audiance....
as far as overall exposure goes, i think wolverine's at the top (at least in the marvel universe)
he's on every cover
Uncanny X-Men, X-Men, Ultimate X-Men, Weapon X, Wolverine, Wolverine/Punisher, Wolverine/Spider-Man, Avengers, Wolverine/Elektra, Sabretooth, X-Men Academy, Wolverine: The End,
X-Men: The End- Book One, X-Men/Fantastic Four
....i mean, jesus christ...give the guy a break already. 🍺
Superman and Batman are DC's most popular heroes. Spiderman and Wolverine are Marvel's most popular heroes. Marvel usually sells more comics than DC, so Spiderman has probably been the most popular among comic fans for almost his entire career. However, marvel has not been making big budget movies until about the last 10 years. Thus, Superman has been the most popular mainstream hero in the past. Also, Superman is the first superhero and known to be the "ideal" superhero. Recently, Marvel has been making big budget movies. The movie "Spiderman" did very well money wise and broke all sorts of records. Considering that, Spiderman is currently the most likely candidate to be the most popular mainstream superhero.