I'd like to chime in to provide some more info to those unfamiliar with the concept. Crash cooling is the last step before transferring the beer out of the fermenter. The point of crash cooling is to drop everything that is in suspension for a clearer beer. If you wait until after crash cool to dry hop, you're negating the reason you crash cooled in the first place. If you're serious (and a little crazy) about getting the maximum flavor and aroma out of your hops after fermentation, pick up a HopRocket.
Side note for those that bottle: Crash cooling is a great way to prepare for bottle conditioning with a different yeast.
Related HomeBrewTalk thread.