Well, my favorite EQ was the original, non-expansioned version.
I consider Kunark and Velious to be essentially the same quality expansion, but I voted for Velious ultimately. Loved both of them since I think they brought the game into a little better balance. The stories for them were cool, they didn't overdo it with new races since they didn't add one in Velious. I remember how amazing it was finding the lost Coldain town at the bottom of the crystal caverns... pure fun. When the Coldain lost the shawl quest war, having the city despawn all NPCs and respawn with corpses was great, lots of immersion. Just great memories overall.
And apologies, but I thought the expansions past that went kind of downhill
Although, Sanctus Seru was a really cool city and doing the quest chain up to killing the leader (Dang, forgot his name) was pretty fun.