How long ago did I suggest this? I don't even remember the last time I suggested a Census poll. And why the hell didn't I put Billy Preston and Eric Clapton as choices?!
I vote for Martin since he was so instrumental (ha! get it? instrumental!) in developing their sound and raising the level of their musicianship.
There was no fifth Beatle. There were people who contributed greatly to their music, former members, and their amazing manager(s). I wouldn't call any of them the fifth Beatle. That's like calling my mom the second harpuah, or the people who formerly held my job position the third, fourth, fifth, sixth, etc harpuah.
love billy, but that's just silly. he played a significant role, but on one of their least significant records. on the other hand, martin played on stuff and was an essential part of their recording process through their whole career. not saying he's the fifth beatle, but definitely the closest thing.
No Sir George Martin, mostly no Sgt. Pepper. Of course John and Paul were the major driving forces but George gave the album the orchestral expertise to give it the polish. Could another producer have helped them achieve this ambition? We'll never know. But it doesn't change the fact that he was indeed there. I think Spector's Let It Be is a true testament as to how influential Martin was.
Bottom line, I agree with this. The four of them are the only Beatles. Now and forever. Still, the person who has the best case to stand beside them (albeit a few steps behind ) is George Martin.