Marvel’s comics are computer-lettered these days (as are the significant majority of comics). I believe that most of Marvel’s comics are lettered by members of Comicraft, an outside lettering company. Comicraft sells the fonts it has designed. As far as what font in particular was used in any given book, I bet that if you’re looking to buy someone at Comicraft would let you know.
I’m sure it’s a relaxed version of the engineering lettering (gothic) style. Of course, I’m referring to the way it used to be, and not the situation that Cliffy’s post addresses (and possibly wholly answers).