To avoid giving spoilers for book 4, I'd say my closest analogue to Snape is Tommy Lee Jones' character in The Fugitive - it's not that he's a "bad guy", he's just a stickler for the rules and doesn't necessarily care about what's right...
If you want more details and/or spoilers, ask me offline...
Offsides
Drunkard's Walk Forum Moderator and Prereader At Large
If you want more details and/or spoilers, ask me offline...
Offsides
Drunkard's Walk Forum Moderator and Prereader At Large