Probably King Kamayam…err whatever
It’s impossible to maximize both fame and frequency of misspelling at the same time, except in the wildly improbable case that the most famous person in the history of the world (whose name was originally spelled in the Latin alphabet) happens also to be the person whose name is misspelled more often than any other. To get an objectively correct answer you need to qualify what you mean by “most famous” and how common a misspelling has to be to qualify as “routinely misspelled.” Nevertheless, here are a few names of fairly famous people I’ve noticed that seem to be pretty commonly misspelled.
Adolf Hitler (not Adolph)
Mother Teresa (not Theresa)
Leonardo DiCaprio (not di Caprio, Di Caprio, Dicaprio, de Caprio, etc)
Michelangelo (not Michaelangelo)
Alfred Nobel (not Noble)
Jim Carrey (not Carey)
Berry Gordy (not Barry)
Robert De Niro (not de Niro, di Nero, etc)
That reminds it is pro wrestler “Eddy” Guerrero Not Eddie. Even his Wikipedia article spells this wrong but pro wrestler reporter Dave Meltzer has said Guerrero always spelt it E-D-D-Y when he corresponded with him
Speaking of pro wrestlers it is Curt Hennig-not Henning.
Arnold Schwarzenegger.
For the former Saturday Night Live and Friends stars, I only in this thread noticed their correct spellings (after checking on Google)-mind blown. Berenstein err Berenstain Bears time again…
Other sports ones I often see which drive me batty:
Mark McGuire
Cal Ripkin [Jr./Sr.]
Craig Nettles [or Greg]
Matt Holiday [need a 2nd el there]
I, umm, did that on purpose. Yeah. That’s it. It was a pun. No, not a pun. What’s that thing that’s the same spelled backwards and forwards?
Yeah, I wasn’t sure if you were calling Gaudere’s Law on me or jokingly calling it on yourself. The latter, it turns out.
Barbra Streisand?
since so many names with Barbara
Dan Quaile.
Actually, I was was calling you out just for dropping the C, and only just realized now that you were intentionally making many errors in the name. 
Well, I wasn’t calling someone else out for an error though, so I didn’t pull a Gaudere. In fact I said I intentionally wasn’t looking up the name and attempting to spell it (most likely wrong) from memory to prove my own point that it’s a hard name to spell.
Garry Kasparov deserves a mention.
The irony here is that she chose that name in honor of a saint who did use the “h” in her spelling.
But I don’t think that Schwarzenegger and the like would count, here: Lots of people don’t know how to spell his name, but they know that they don’t know, and so if it’s ever relevant, they’ll look it up. But most people probably thought they knew how to spell Courteney Cox’s name, and so never bothered to look it up.
Wow, I don’t think I’ve ever before been guilty of so many misreadings, misunderstandings, corrections, and corrections of corrections here at SDMB.
When I first saw your Schwarzenegger post, I just noticed that you had left out the C. I missed the other misspelling (extra T), and I didn’t even read the rest of the post to see that you weren’t trying to provide the correct spelling.
Before I jumped in with my first “correction” of you, I checked to make sure that there really was a C, but I didn’t notice that there wasn’t a T. So I became Gaudere’s victim while, as you point out, mistakenly claiming you were.
Then @Kron called me out, and you followed up, implying that you hadn’t pulled a Gaudere, which confused me. I posted again, making several ETA changes while you were posting your latest comment. When I read that, I finally went back and more carefully read your first post and realized the enormity of my errors. 
I blame the fact that I only had 4.5 hours of sleep last night.
Ha, well I guess it’s appropriate in a thread about misspellings!
Pee-wee Herman, not Peewee or Pee Wee.
Is it Brittany Spears and Britney Murphy? Or the other way around? I always have to think of them, since I frequently drive past an apartment complex named The Brittneys. ARGH
In the science fiction world, Samuel R. Delany was once the biggest of names. Everybody spelled it Delaney. My spellcheck wants to spell it Delaney.
For that matter, I’ve seen Isaac Asimov’s name spelled Azimov about a zillion times.
It’s also Frederik Pohl and Fredric Brown. Neither is a Frederick as people like to dub them.
Note the complicated reason given below why his name was spelled with an s and not a z. Most people of that name in coming to the U.S. took the name Azimov, There are more people in the U.S. spelling it with a z:
I’m not sure if it counts since Shakespeare spelled his own name several different ways, but I read that his name is spelled in over 20 ways in over 20 languages.