About time someone mentioned Harvey....There's way too many pop icons in the list and not enough actual icons. I can also see Lance Bass (major pop star who outed himself). Of course, if I wanted to throw in a pop star, it would Cher, but only because she's one of the few that's earned it (ie, done things for gay causes more than just made music). 
TR Knight I can't really call an icon; he's a great actor, but he's only known for being outed by He Who Shall Not Be Named. If you wanted to go that route Shawn Pyfrom (sp?) is a better bet, as he created one of the best known gay characters, even if he is straight. I would also nominate Gale Harold and Ryan Harrison, as well as the other main characters from QAF, as well as Sean Hayes (and not for "Just Jack"!) for showing different aspects of being gay. Of course, it would be hard to not mention Rock Hudson, even though his homosexuality was only revealed after his death. Just for some youth, I'd throw in Jonathan Taylor Thomas; he may straight, but his willingness to play gay characters and his role in Common Ground should count for something (as well as Stephen Weber, and do I really need to mention Jeffrey (one of the best AIDS movies?). 
As far as other actors go, I'd really debate them; too many actors have played gay roles, but not enough have developed gay characters are done much for the cause. Alexis Arquette is a star in this mold; do you really want to see him as an icon?
Although it may weird to include fictional characters, I would need to include Northstar (as the first mainstream gay superhero), Midnight and Apollo (gay superheroes that had actual power, and whose writers have fun with their sexuality), and George Lipincott (who is probably the best fictional icon here, even though he was one of the best to represent AIDS (from Doonesbury, BTW)). I know that there would be votes for Anole, but I'd prefer that Hulkling and Wiccan get the vote. 
Of course, I would need to include Michaelangelo; I just wish I could remember other historical figures, but he should be an excellent for the rest. 
Too bad the article is theoretically done with...
RG