>I reckon OK wins it by miles
okay.

which do y'all prefer in writing, OK or okay?

most of the dispute over the origin of the word has apparently been resolved..

http://en.wikipedia.org/wiki/Okay
http://www.bartleby.com/61/12/O0051200.html

fwiw, ænigma gives Okamoto for OK. but what about OKlahoma?!