I'm a big fan of silent spell and still spell. Not only are they great for emergencies (like when you are bound and gagged) but used in combination you can cast a spell with very little chance of being noticed.
which then added to Quicken spell like ability allows you to put out quite a bit of oomph for 3 rounds. Innate is in the FRPG (i don't remember if it's in th FRCS. quicken spell like ability is in the MM.