The Inquisition offers one of the largest ranges of potential forces to be wielded in an army; they can requisition forces from the Imperial Guard or the Space marines as well as the forces of the Ordo Militant and Imperial Assassins.
What is your prefered force? do you stick rigidly to forces of the Ordo Malleus, such as Daemonhost, Inquisitorial Storm Troopers, Inquisitorial Chimeras etc. Or do you side more heavily with the Grey Knights?