I'd say it's kinda sad that Bruce Wayne has become the mask in the modern comics.

I've been reading golden age archives stuff and I would say the most interesting, though it seems under utilized, secret identity has to be Freddy Freeman, Captain Marvel Jr.'s alter ego. A disabled boy who walks with a crutch and can use this disguise. There's one story where Jr. disguises himself as Freddy which I thought was interesting.

Wesley Dodds has some intereting moments. Particularly the story where his two air force buddies and he fight some villains in planes and while Dodds never dons his costume the villains assume there are three Sandmen. One in each plane. Dodds at least got more usage out of his alter ego than many do now.

Right now I'm around the fifth story of Golden Age Starman Archives Vol. 1 and his alter ego is rather dorky. Ted Knight is always feigning illness to make himself seem weak to his friends so as to disguise himself as Starman. In fact, it's done so much that his girlfriend is trying to hook up with Starman. Strangely this all takes place in Gotham City!?! Maybe she should try hooking up with Batman.

Mikey
"It's In The Giving, Not The Getting"

"crip props are almost as good as regular american props!"-The Indefatigable Fjor