Anyway, the excuse for pulling in "Twilight" ("Twilight," "Twilight") is Mr. Rewrite's recent quest to confirm whether vampires and co-eds who love them gaze into each others, each others' or each other's eyes.
Thank goodness Mr. Rewrite spent Rewrite Jr.'s college fund on expensive usage guides. They came through for him again.
The answer: They gaze into each other's eyes, are at each other's throats, have each other's backs, etc. In Common Errors in English Usage, Paul Brians notes that the reciprocal pronoun each other is singular, adding that reworking the sentence reveals the logic behind each other's: Each gazed into the other's eyes.
In The Elephants of Style, Bill Walsh writes that other in the compound is inherently singular, making each other's the way to go in every case.
In Garner's Modern American Usage, Bryan A. Garner (cue angelic chorus) notes that the noun following each other's is often plural but that often the more logical construction is singular. With that in mind, Mr. Rewrite almost went with each other's back and each other's throat, but it just sounds better as each other's backs/throats and still seems logical grammatically and visually.
That said, Mr. Rewrite is often wrong, as today's bellybutton/belly button Twitter disaster proves (go with bellybutton, per the New World).
Garner adds that the tendency to go with each others or each others' seems to stem from a sense of plurality overriding the notion of reciprocity.
Not surprisingly, there's quite a bit of confusion on this point among news organizations and wannabe news organizations. A Google News search turns up hundreds of uses of each others/others' and even a handful of eachothers.
Favre, not Brett Farve or Bret Favre or Bret Farve. As the ageless wonder comes back for yet another season, Mr. Rewrite is seeing quite a few misspellings by news organizations and wannabe news organizations.