spider man must have a secret ID or else his family will suffer AND he will be sued all the time.
REED RICHARDS - doesn't need a SID everybodu knows him and his family and friends are powerful enough to take care of themselves.
so who else need/doesn't need it?
In my opinion, anyone who's an official member of the Avengers, the FF or the X-Men doesn't need a secret identity. It's one thing to say that the Kingpin (or someone similar) would go after Spider-man's family, but I think Mr. Fisk would reconsider making a blood enemy of Spider-Man if he knew he'd be facing retaliation from the likes of Iron Man and Thor. This applies to members of any organized team like the three I mentioned. And the Hulk definitely doesn't need one - almost everyone he's ever been related to or friends with is now gamma irradiated in their own right these days (Betty, Gen. Ross, Jen Walters, Rick Jones, Doc Samson).
I think every mutant is registered anyway, so the X-Men's identities aren't really a secret. Ditto with the FF and an increasing amount of Avengers (Steve Rogers, Iron Man, Luke Cage, Iron Fist, Hawkeye, Mockingbird, Black Widow, Carol Danvers, Hank Pym, Janet Van Dyne, Wonder Man, Black Panther...).