Just wanted to give some love to Lord of the Rings Online! I was extremely surprised picking up this game for the first time recently.
Unfortunately I started playing a couple of days before the WoW Forever beta, but I think LotRO will become a permanent addition to my MMO repertoire between WoW sessions.
My favorite LotRO experience was the open beta. Characters were capped at a very low level but most of the world was open to explore. So as a plucky hobbit thief, I snuck around some preposterously dangerous areas. In that game, when there are powerful enemies present, it has an Eye of Sauron effect on the screen, like when Frodo puts on the ring. So I'm sneaking around/running for my life in these dark, deadly areas, all while being oppressively harrassed by THE EYE at the edges of the screen and filling the ambience. So visceral I remember it 20 years later.