Age of Empires 2 might have reached its peak. But there’s enough meat on it for Age of Empires 2 Definition Edition to last. HD coming second and The Conquerors as third.
Anyway, my favorite civilzations would be the Asian ones. To be fair I’ll pick one in each game category.
The Age of Kings: Japanese.
The Conquerors: Koreans.
Others in no particular order: Chinese, Khmer, Mongols, Malay.
Second the Malay choice. Their eco bonus is creative, requires adaptation and planning and is fun. I also enjoy Persians for black forest war elephants (very satisfying if you get there) and Lithuanians in general (smooth start and relic bonus is interesting and drives the direction of a lot of games).
My favourite is the Incas, and there’s no reason for it I think. Maybe relatively early when I started playing HD, I had a teamgame and my two allies were dead or something, so I was 1v3 and felt like I could’ve beaten them all if any of my allies still were alive. Beauty of the counters!
Now, it’s just the beauty of the Kamayuk.
If we had to choose one from each game, probably Japanese (I love the East Asian architecture, specifically the mill for some reason. Water wheel!!), then either one of the meso civs or Huns, Incas, Berbers, Malay or Vietnamese, Tatars or Lithuanians, Burgundians, Poles, Dravidians or Hindustanis.
Burmese is in HD. Not a new one in DE.
Bengalis due to their UU the Rathas.
I’m a Berbers picker, mostly. (Or was at least, and hopefully will be reasonably soon) I also like Persians. I haven’t had much chance to try Gurjaras yet due to dragging wrist problems, but I like the concept. I’ll especially like it ones it gets tweaked down a bit. Byzantines are nice too, and some non-camel civs as well. Magyars, Franks, anything where you can make lots of cavalry…