Yeah antimagic field is up there.. I'd suggest something a bit more progressive, something along the lines of a protection domain cleric. At low levels, having access to abilities designed to ruin spellcasters in a more subtle way - distraction spells like color spray and pyrotechnics, dispel magic, globe of invulnerability, etc, and then gaining access to Antimagic field at a (Much) later level. Adding spell resistance perhaps instead of fighter bonus feats, and gaining the other powers as spell-like abilities in exchange for never gaining magical benefits?
