So forget movies and TV.  In the comics, who do you think has the most believable/convincing secret identity (and why)?  Who has the worst?

I think the best is Iron Man, because his head is totally covered and I imagine his voice is modified through a speaker.  The worst for me is Green Arrow--with that unique mustache and beard, even in civilian clothes, I think anyone would be like "hey aren't you Green Arrow??" 

It made me realize--I imagine the same thing would be true in Star City!  I bet there are a thousand men in Star City who would get goatees just like the Neal Adams Green Arrow!  Oliver Queen is just another "fan"!

Likewise, Superman's identity also works--in comics!  I TOTALLY believe that someone like the Earth 1 Superman has total control over his face muscles and voice.  Just by clenching his jaw just a little, I bet Superman's face could look rock hard, while Clark Kent probably has no obvious cheekbones or other hardness in his face.  (Not to mention that Jerry Siegel and Joe Shuster--I believe it was them--gave the Golden Age Superman the actual power to adjust his face!)

I think any of the full-face masks work pretty well.  Dr. Fate is best, though Iron Man should work for all the reasons you say.  I bet the comic book Spider-Man works too (the movie actors WANT to be identifiable to the audience!)--really nobody should ever suspect that the adult-looking Spider-Man was a 15 year-old high school kid (at the beginning).

Daredevil is pretty good too.  Again, it should NEVER enter anyone's mind that a blind man could be an acrobatic super-hero with great aim.

After that, Daredevil is also one of the better ones for me; the one that immediately sprang to mind.

Of course, it also helps that during Ollie's run for mayor of Star City in World's Finest, he appeared publicly with Green Arrow at a number of events courtesy of GL's power ring disguising another member of the JLA. Similarly, Tony Stark has been photographed numerous times alongside Iron Man, his former bodyguard, with one or the other as SHIELD LMD's. It doesn't have to happen too often for it to be effective.

Plastic Man's identity is a well-kept secret since he alters his facial structure entirely whenever he resumes his role as criminal "Eel" O'Brien. He doesn't live his life as Eel, however, only taking on the part when investigating crimes among his old community of lowlifes.

Peter, I agree that characters involving total transformations should be the hardest to associate with one another, except that it only takes a couple of occurrences when an emergency happens right in front of them and they must transform publicly for those to come into question.

Also, I love that you wrote "Billy Batson and Captain Hero." Captain Hero, a.k.a. Jughead, was similar to Cpt. Marvel in the sense that he only had to shout a magic phrase to turn into a mighty champion of justice, in his case, "Teeny Weenie Magic Beanie, Pointing Towards the Sky! Bring Me Muscle, Power, Vigor! Form a Super Guy!" He had one of the most obvious resemblances to his actual self since he still wore his trademark hat in both identities. In his case, as with Pureheart the Powerful (Archie), Superteen (Betty), and Evilheart (Reggie) they were all protected by the "PH Factor," a memory-fogging effect that would inevitably follow any of their super appearances, causing the public to forget that the super-heroes had even shown up.

Best one: has to be Daredevil.

I agree as far as the comics go.

I did used to think about this whilst watching the live-action Hulk series. Jack McGee saw the Hulk numerous times in the first season. On one occasion ("The Hulk Breaks Las Vegas"), McGee is close to Hulk, who is wearing only jeans; in "Terror in Times Square", he sees Hulk wearing jeans and a ripped shirt. Did he think the Hulk was changing into different kinds of ripped clothes as he went from city to city? 

Not to mention the fact that Hulk's face began to change in "The Hulk Breaks Las Vegas". A crook shot him, reversing the change to Banner, but McGee must surely have had suspicions early on in the season.

*SPOILERS FOR THE SERIES*

McGee learnt that the Hulk was really a man in the two-part "Mystery Man" (Season 2).

Worst - I'm minded to think that a public ID would fall into this - so maybe the Fantastic Four or the Elongated Man, or (now) Iron Man, Captain America, the Hulk, etc.

DISCUSSIONS: Superman was shown with the face shaping ability once, or perhaps twice. I'm not sure that counts as an ability. Of course, he can make himself sound like anyone he wishes.

Captain Hero looks exactly the same as Jughead. That's the same reason I wouldn't pick Mary Marvel or Captain Marvel Jr. as best in addition to Cap.

The Hulk is questionable. If one DIDN'T see his transformation, then no one would ever suspect; I think it was once established that even Banner's and Hulk's faces are different.

On the other hand, Banner has often been unable to run and hide when he transforms, and the Hulk just hasn't thought of it. So it would likely be pretty obvious after being observed once or twice publicly.