I'm so glad I just recently came back to this game (the free weekend ensnared me, and now I am a paying subscriber again). This game is so great on many different levels - and I can't help but think of them as I explore moria. I've been around the block, so to say, and have tried just about every major MMO, and this game continues to be a standout for a few reasons:

1. Epic feel. There have been moments where my jaw literally drops at the artwork and design of moria - I've had several times where I've yelled to my wife, "Come here look at this room!". The areas are beautiful, and the graphics engine is excellent.
2. Quests - as most people know, the quests are excellent, as is the story line. I love the voiceovers you get at most instances, as do I love the cut-scenes you get to "unlock" as you do the epic quests. I also love the instances in this game. It's so great when you come across a new instance, especially ones like where you get to play a Dwarf right before the fall of moria, and get to re-live the first encounter with the Balrog that they awoke!
3. Community - most people are just straight up good people that love Tolkien and this game. *standard disclaimer applies here, of course there's always going to be the idiots as well.

There are many more reasons why I'm very happy I came back, but those are the top three.