I rolled a drow wizard who took a 1 level dip into bard at first level. I'm trying to plan out how to spend feats. I'm level 3 now. So far I have Mental Toughness and Extend Spell. Feats I think are probably must have later would be Improved Mental Toughness, the Spell Penetration feats, Heighten Spell and probably Skill Focus: UMD. What would you say are other "must-have" feats?