Its pretty much no question that Curt Schilling and Mike Mussina were by FAR the biggest snubs.

Schilling 10-3 3.64 109 k's 14 walks, 1.10 whip

Mussina 10-3 3.24 108 k's, 23 walks, 1.04 whip.

These guys, if they continue on like they are, will be right there at the end for the cy young.