Take Ruby Ray!
(Of course, first take Project Image and Mordekein's Sword.)
Ruby Ray of Reversal is a wonderful spell. It's only level 7, but removes Spell Trap. As a Sorcerer, you'll have many, many uses for your level 9 spells -- no need to waste one casting Spellstrike when a mere Ruby Ray would do. Also, Ruby Ray can be put in Chain Contingencies, while Spellstrike cannot.
Some people recommend you take both, but I've never had to use Spellstrike. In the heat of battle you can always cast Chain Contingency -> Nearest Foe, then put in it Ruby Ray, Pierce Shield and Khelben's Warding Whip.
What other spell(s) are you considering in place of Ruby Ray?
-- Nifft