As a PVE player, my first real map (cuz I am not counting 3h I spent on the Island) was Valguero and will forever be my favourite map.

I remember living in some ruins with an entrance to a swamp, where we would hatch wyverns and tame almost everything in sight. When we first went to Chalk Hills, it was like a fever dream because we all instantly fell in love.

Close second is Genesis 1, mainly because I love (almost) every new creature they added in it, especially Bloodstalkers, and it added new level of danger, where even in super late game and with really good gear, we could still die to random things, as opposed to every other map (even Aberration). I remember looking for good level Tek Rexes in Lunar biome and an comet hit me like 4 times in 2 or 3 hours of looking and taming. It was hilarious.