Which villains actually belong in Arkham?

A couple of weeks ago, there was a discussion about this film possibly being an adaptation of A Serious House of Serious Earth. This got me to thinking, if they were to adapt this graphic novel, which villains should they include? That then lead me to question exactly which villains in Batman's rogues gallery could really be classified as criminally insane.

So, who would actually inhabit the madhouse that Arkham built?