What's the build you can't help but come back to?

I've been playing a pyro psyker abomination that murders everything in sight, but I can't help but yearn for the commissar officer. Maybe it's the flavor win of shooting at your allies to give them extra MP and AP, maybe it's because I prefer to let my companions DPS so I can play with the mechanics of all the classes a lot more, or maybe it's just because I'm one of the approximately six weirdos alive that genuinely really likes Grand Strategists.

But whatever it is, every time I fire up this game, I can't help but think about how much I like commissar officers again.

So it got me wondering what That Build is for other people. What is it for you? What build can you just not stop thinking about when you try playing anything else?