Re: 1+2+3+4+ to infinity = -1/12
Needs to be a Brit to qualify.
Ramanujan's mentor Hardy gets my vote. His work, proudly useless in his own time, now fundamental to modern cryptography. And his discovery of Ramanujan: interesting that an established great mathematician bothered to read the unsolicited work of an unknown Indian, as opposed to putting it straight in the spam!
I would also vote for Bertrand Russell, who might also qualify on grounds other than his science.