Crucial In Any Subtle Investigation
I'm not entirely sure about running the gun servitors as Shooters, though, as Epic 40K HOTT doesn't really handle Shooters as a concept. Although not as armoured as Marines, they may be better classed as Blades and depicted with one more figure on the base than Space Marines. Praetorian Servitors could be run like Dreadnoughts (Blades, but only one or two figures) and may even work as Knights if large enough. The elite, specially equipped nature of the Ordo Xenos may run well as a Hero and as such would make an interesting addition to a conventional Space Marine army, depicted as five or six marines from different chapters on a single base.
1 x Magician General @ 4 AP (Inquisitor with retinue)
1 x Magician @ 4 AP (Daemonhost)
1 x Warband @ 2 AP (Arco-flagellents)
2 x Shooters @ 2 AP (Gun servitors)
2 x Knight @ 2 AP (Inquisitorial Land Raiders)
3 x Blades @ 2 AP (Space Marines)
6 x Hordes @ 1 AP (Imperial Guard)
This list represents an inquisitor who believes that to fight the forces of chaos by using their powers against them. Daemonhosts are chaos daemons forcibly bound to a human host by the inquisitor. Arco-flagellents are surgically altered criminals who fight using close combat weapons and cocktails of drugs to boost fighting abilities. Once they start they can only be stopped by a codeword from the inquisitor.
1 x Cleric General @ 3 AP (Inquisitor with retinue)
2 x Clerics @ 3 AP (Grey Knights)
1 x Warband @ 2 AP (Arco-flagellents or religious zealots)
2 x Spears @ 2 AP (Imperial Guard Stormtroopers)
1 x Sneaker @ 1 AP (Death Cult Assassins or Officio Assassinorium)
2 x Knights @ 2 AP (Inquisitorial Land Raiders)
2 x Blades @ 2 AP (Deathwatch Space Marines)
This list represents the inquisitor who fights Chaos in all its form; even those within the ranks of the Inquisition. Imperial Guard stormtroopers are better trained guard units. Deathwatch Space Marines are from the Ordo Xenos and frequently fight alongside inquisitors against alien foes.
Hero General @ 4 AP (Experienced inquisitor with retinue), Cleric @ 3 AP (Psychic 'blanks' individuals who can block psychic energy within a specific area), Airboat @ 3 AP (Thunderhawk Gunship or Cutter).
White Dwarf magazine, Inquisitor Rule Book, The Eisenhorn Trilogy by Dan Abnett. (Xenos, Heriticus and Malleus feature an inquisitor as the main character. Well worth reading for inspiration.)