George Martin
Actually, at the time, the only person ever mentioned in this context was Billy Preston. It was a big hype fest, of course. So he played a few keyboards; big deal.
In Billy Preston’s defense. The other four Beatles were the ones who refered to him as “the fifth Beatle” so it is not entirely unjustified. The others who wear that title got it applied to them by the media.
I really thought it was Pete Best, the original drummer, but I guess I was wrong.
I was wrong once before. I thought Disco would last.
It did last. Haven’t you heard of Madonna? 
Apu.
Years back, when the movie “Backbeat” (about the Beatles days in Hamburg in the early Sixties) was being made, the director sought some advice from Ringo Starr. Ringo told them, “The main thing is, don’t try to sound like the Beatles. Because THEY didn’t sound anything like the Beatles back then.”
Good advice- because the instantly recognizable Beatle sound is, to a large degree, George Martin’s creation. No, he didn’t write the music, nor has he had any huge success without the Beatles… but his contribution to the boys’ sound was crucial. If anyone deserves the title “5th Beatle,” it’s definitely George Martin.
I am Spartacus Fifth Beatle!
This.
Neil Aspinal or Mal Evans. Both were with the band (as roadies/road-managers/business associates) from the beginning.
George Martin. As others have said, he had far more influence on the SOUND of the Beatles than any of the other people mentioned.
George Martin.
I remember watching some crappy sit-com where the main character was on a terrible blind date. The guy couldn’t stop talking about the documentary he was making about the band’s long-term tour bus driver, who was so important he had earned the moniker “The Eighth Beatle.” The rest of the show has been eminently forgettable, but that line made me guffaw, and it’s the first thing I always think about whenever the question of the Fifth Beatle comes up. Well, that and Clarence.
–Cliffy
I’ll add to the George Martin chorus.
Run right out and rent the DVD of Back Beat!
(Which, BTW, features a lot of music but no Beatles songs, because Michael Jackson owned the rights to them at the time, may he be reincarnated a boywhore in the sleaziest brothel in all the Third World and he shouldn’t even enjoy it.)
I don’t know. It is true that Martin made a huge contribution to their later sound, and for that he probably more deserves to be called the fifth Beatle than anybody else. However, did he really do much more for their early records than stick a few mikes in front of them and work the faders? I believe their first album, Please Please Me, was recorded in a single day, and I imagine it was basically their stage repertoire from the Cavern. Their sound did not change enormously over the next three albums. It is really only with Help (the album more than the single) that their sound began to change and mature, and Martin’s contribution starts to become more and more noticeable (and, eventually, huge).
If their sound changed a lot between the Hamburg days and their early hits, that probably had more to do with the fairly drastic lineup changes than with Martin’s influence. In Hamburg they had a second rate drummer (Best), by all accounts a quite hopeless bassist (Sutcliffe), and three guitarists. It was Paul moving to bass, and (probably to a lesser extent) Ringo taking over the drums that made the Beatles’ sound come together.
By the way, IMHO the fact that Wikipedia has a quite extensive page on this topic does not reflect particularly well on the encyclopedia.And of course the sixth Beatle was Ringo.
Shemp.
No, seriously, it refers to the 2nd Paul, the one that took the original Paul’s place after his death was covered up in 1966.
What do they call Brian Epstein in heaven?
A: The third Beatle.
In strictly literal terms, it would have to be Pete Best. The band started calling themselves The Beatles in early 1960 when it included Lennon, McCartney, Harrison, and Sutcliffe. Then Best joined in August. Whatever other members came and went, before they were called Beatles don’t count. They were Quarrymen or Moondogs or whatever.
When it comes to the Hamburg period, most if not all of what we have probably has Ringo playing and not Pete. Stu was long gone, actually dead by the time the tapes that eventually became the “Beatles: Live At The Star Club” album. The way a band plays in a nightclub is usually different from how they do it in the studio; the earliest studio recordings–the Decca and Parlophone auditions, “How Do You Do It”, and “Love Me Do”, seem to reveal their desire (or pressure on them) to record accessible pop songs with hummable melodies and audible lyrics. (Though they did hate "How Do You Do It.)
Regarding Stu Sutcliffe, the Beatles seem to have been a lot better satisfied with his bass playing than they ever were with Best’s drumming, and Stu did leave voluntarily, remaining friendly with his former bandmates until his death. Moreover, an interview with Bill Harry, publisher of Mersey Beat, suggests strongly that reports Stu’s utter lack of musical prowess was an exaggeration. Not that he was a great player, like Paul McCartney or Jack Bruce or what have you. But he probably could turn in a reasonably competent, workmanlike performance.