If 40k was real what army/faction would you join?

Keep it somewhat realistic. By that I mean do you really want to join the chaos or the tyranids? Do you really want to go through the genetic augmentation of the Adeptus Astartes, or the cybernetic augmentation of the Adeptus Mechanicus?

What role would you want to serve in your army/faction? A Blood Angels Sanguinary Priest? A Imperial Guard Sniper? an Inquisition War Acolyte? A Tau Gue'vesa? A Skitarii Ranger? A Iron Hands Forge Father? Something evil?

I would probably go with either an Adeptus Mechanicus Enginseer assigned to the Imperial Guard, or either an Imperial Guard or Imperial Navy officer stationed on Mars working with the Adeptus Mechanicus sort of as a liaison officer.

What about you all?