Going strictly with PHB feats, I would also recommend Scribe Scroll. Someone also mentioned Improved Turning, which I think is probably as good as any other option, at least first or third level. At low levels, it can make a big difference. In fact, in our last session, our cleric 1/wizard 3 (the only cleric in the party), made two critical turn checks against some krenshar skeletons and lizardfolk zombies. Without this feat, he would have failed both checks, and the feat also helped his turn damage such that all of the undead but one zombie were turned. It's only a +1 to your level, but it does affect both your turn check and your turn damage.
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