I love the act V music. I always find myself singing/humming along with the notes, not so much with other acts. Although act VI has good music too, but I just hate all the staircases in the buildings so I couldn’t vote for it. Also aetherfire on the ground is annoying.
Act one for sure cause you are starting a new character and feel awesome killing stuff and learning new skills. Looks wise the new Ugdenbog is cool but as far as a whole in play through endgame new acts are terrible, prefer game before expansion.
Act VI.
Theodin and Aleksander fights are just too good, and the ambiance/setting is mindblowing.
Theodin’s fight as much as I hate to say it is much more interesting than Loghorrean. Kinda unfair 
For me, it’s act 6 for sure.
The music is amazing, and the aesthetics, with all of the shop signs etc. in the ravaged city of Malmouth are really stunning - the amount of work that’s gone into the fine details of the environment (incl. lore notes) is breathtaking. Malmouth gives me a very similar vibe to Dishonored (well, with more wanton destruction) , which is an aesthetic that I really like.
I also like the aetherials as an enemy, especially with all that one learns about them, their goals, and internal divisions.
TBH, the only areas in the game that I’m not all that keen on, aesthetics-wise, are the Chthonic areas. Conceptually, they also don’t quite gel for me - I don’t get what obsidian has to do with Chthon, and the reliance on this is quite a contrast with the blood-harvesting theme for the cult. I may have missed something, though I can of course see that an obsidian-based "life"form doesn’t require blood, so would be an efficient option in the absence of any blood.
Dude, your next minion is just going to have to bring a better game, then. Take it up with Log, don’t come whining about it here…
Also, I think you may have meant to end with “Sad!”, not so?
Love act 2 et 5 ; sorry can’t choose so i didn’t vote for anything
Tough call between Act V and Act III. I love the abandoned village, Blood Grove, and Darkvale Gate, but Act V is beautiful to look at and the best paced outside of Act I.
The art direction in Malmouth is fantastic, so I’ll vote for that.
Act II is the weakest part of the game, imo.