I had a friend build a surprisingly effective Dragonborn Sorcerer/Elemental Savant. The Savant levels helped somewhat, but the real killer was the combination of Arcane Thesis (Fireball), Energy Admixture, Versatile Spellcaster, Practical Metamagic, etc., to make a "super-fireball" which did 20d6 of fire damage using two 3rd level spell slots. Half the campaign devolved to "doors open, everything burns." Heck, he even threw on Searing Spell to bypass fire immunity and resistance, and thanks to Arcane Thesis it cost nothing! Disgusting. If you face lots of high SR creatures, through the Thesis on Orb of Fire and flavor to taste.