I'm using quicken, empower, and violate spell from the Book of Vile darkness, which has some real differences. check them out! My DM calls them "Quicken Vile spell like ability" and "Empower vile spell like ability"
Pretty neat.
quicken for instance, lets you use the quicken power on ANY and ALL of your SLA's 1/day.
Empower allows you to use Empower on ANY and ALL of your SLA's 2/day. This isnt as bad as it sounds, as the warlock has very few SLA's which are targets for this power.
Finally,
Violate spell like ability is awesome for a warlock. 1/2 his damage cant be healed except in a consecrate or hallow effect. nasty!