Sad but true: One of the greatest Assistant District Attorneys in the history of the Law & Order franchise, Diane Neal as Casey Novak, has left the show. It was announced today that One Tree Hill alum Michaela McManus will be replacing her. One Tree Hill abstainers that we are, we can't attest to McManus' merits; but they better be plentiful, because she's got some big sensible heels to fill.

After the jump, every single ADA from Law & Order's history. Who's your favorite?

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