No need to PM me as I am RIGHT HERE.
First of all read Absolute Terror. Detective Comics 835 and 836.
Scarecrow: Year One is good, but it's not technically canon.
Joker's Asylum has a really good Scarecrow issue.
There's a part in the Knightfall saga called God of Fear which is good.
His appearance in No Man's Land is pretty great too (the whole freakin' story of No Man's Land is a must read though).
I'll post more as I think of them.
--
~Halo Now darkness takes you... forever.