If you could be anyone in 40k...

[Connjurus]

The Princeps of an Imperator-class Warmonger Titan.

Fear me, for I am death to you and your world. Deus Machina Est. God is Machine.

Now, why? Because it would be me, not the Space Marines, not the Imperial Guard, not the Sisters of Battle, but ME who wins the battle for a planet.

Failing that, an Arch-Magos Seniorus or a Magos-Secutor, so that I could slay in the name of great Machine-Emperor, the Omnissiah.

Those two, or a Sorceror-Lord of the Thousand Sons under the command of Ahriman, so that all the knowledge in the galaxy could one day be mine.

[Herald of Nurgle]

I would have to be a Chaos Spawn.

Free food, free housing, no real expectations... no negative impact on my army by denying them valuable Fast Attack slots :P

[Sangre]

A fat, happy, well-to-do bureaucrat on Terra, blissfully unaware that the galaxy is falling apart, and safe on the most heavily fortified planet in the galaxy.

...What?

This man is a man after my own heart. I'd be a happy middle-class merchant on a civilised world, way, way behind the front-lines. Ain't got no worries.

[Artein]

I am Alpharius.
We are all Alpharius.
We are the Alpha Legion, we are one.

So yeah, an Alpha Legionnaire.

Or a normal guy on a planet as far away from the Eye of Terror, the Eastern Fringe, Ork worlds, Necrons' tomb worlds as possible.
I'd be perfectly happy never seeing Xenos, heretics or Astartes.

[Aldramelech]

The Guy who clips the Emperors toenails......

Imagine how much their worth!

[DarkAngelHopeful]

After having read Mechanicum, maybe a pilot for a Knight or possible a Princeps for a titan.

I like the idea of being a "God of War" on the battle field. Plus, being a Knight pilot or Princeps seems to allow that you could have a spousal relationship and a family, where as if I chose to be a Space Marine I wouldn't be able to. It all comes down to the fun and mayhem of driving a titan and being able to have a family.

[HP Delron]

Someone from a minor noble family on a planet well insulated from the front lines. I'd want to be relatively unimportant member of my family. Ideally I would get a fairly comfortable life out my connections but I wouldn't be relevant enough for anyone to want to assassinate me. I'd keep my head low, stay pious and never try to butt into anyone's business.

[rbryce]

id be the priest in my army, cos that was the pupose of him in the first place! lol. hes a priest serving under the adepta sororitas on the shrineworld. almost like an indentured servent, he can trace his families service to the faith back for millenia. usually toting a boltgun or flamer, hes an upfront kinda guy, often seen at the fore of battle, delivering holy judgement with fierce oratory. other times he has been seen walking the hall's of the sanctorum chanting liturgies softly, praying to the God-Emperor for the deliverence of all the innocent souls lost during the many progroms and wars of faith he has been involved in.

[Wulff]

Black Templar Emperor's Champion would be my niche..

I would always have something to do.. cause there is always a crusade going on.. i'd get to meet the nicest"as they plead off their knees" and most well dressed "such as farseers and warlocks and the various Wyche type" folks and destroy them.. I would hunt down psychers as the abominations they are and give them the emperor's justice.. and I'd get to recite my Vows for battle with all my comrades..
Templars don;t answer to any but Templars so it gives me a bit of a break from those annoying inquistor types.. and best of all.. i get to wear my black formal suit everyday!!

Wulff

[RocketRollRebel]

Vostroyan Imperial Guardsmen. Best uniforms, Rozvod!, good training and gear and the best friggin mustaches in the galaxy! If you're gonna go waste the enemies of man kind you might as well look good while doing it. Not sure what specifically. Maybe command a Leman Russ Punisher. That thing would be so fun.

Or maybe Space Wolf on a thunderwolf. Fenrisian Ale, being a little nuts flying into combat. I like their reckless tactics. Kinda how I like to play. Set a goal and go all in, some times works other times falls flat on its face . Plus I work as a dog walker in real life so I love dogs and spend all day with them as it is. I think that would fit well and be a good chapter for me.