Joining my list of characters in need of better shows is Kaminagi from Zegapain. This is not to say that Zegapain was a bad show, but Kaminagi was far and away the best part about it, and it's a shame that the rest of the series couldn't measure up to her awesomeness. (For those of you keeping track, some other characters in need of better shows have included Kotori from the Da Capo series and Aoba from Jinki:Extend.)
Among the many moe stereotypes, you'll frequently find the Childhood Friend. She is a staple of harem comedies and pretty much anything related to dating sims or eroge. One study suggests that the Childhood Friend does quite well for herself, even if she does not necessarily have the inside track.
In addition to the Childhood Friend, you'll also find the Clumsy Girl, the Class Rep, the Athletic Girl, and the Shrine Maiden, among others. Curiously, you won't find the Girl Next Door quite as often.
Perhaps the Girl Next Door is a convention foreign to Japan, at least compared to her stature in American culture. You'll remember that Hugh Hefner built his empire on her charms. He explicitly states that his Playboy centerfolds represent the Girl Next Door. (I would argue that the typical centerfold has looked less and less like "the girl next door" over the years, but you get the idea.)
But where ranks the Girl Next Door among anime cliches? When she does appear, she's sometimes also the Childhood Friend or some other more common cliche. It's like she's just the Girl Next Door by happenstance.
So, while I can't claim the Girl Next Door is rare, she is uncommon where anime is concerned—uncommon and under-appreciated. All glory to the Girl Next Door. When you're with her, it feels like home.