I realize Les Miserables is really cliche for my favorite musical theatre show of all time, but that doesn't mean it is not my favorite. I have multiple reasons.
1) It is the first show I ever saw that wasn't put on by my middle school theatre class. I was 15 and in 10th grade. I will admit I fell asleep at some point, but I was just tired. I woke back up and had renewed enthusiasm for the show, as well as deep interest in musical theatre. In the last 14 years, I have seen the show a total of 4 times (I think...), including 3 times on tour and one time on Broadway in 2001 before it originally closed. I haven't seen the revival, which is now closed on Broadway as well.
2) I purchased, and subsequently memorized, the Original London Cast recording. I have also submitted myself to listening to other cast recordings, and I just find that no one can compare with Valjean (Colm Wilkinson), Javert (Roger Allam), or Marius (Michael Ball) from the Original London Cast. There ARE performances by this cast that are hard to listen to (Turning...) due to the whiny ensemble cast. But for the most part, what I love about this cast is that you can hear their passion.
3) The overall story of redemption is excellent. This is one of those books I have planned on reading for years and have just not gotten around to it. I am sure the book is amazing because there is so much that had to have been left out of the musical version (even more so from the movie versions). I love the use of dead characters to duet with the living, in ways to encourage them or welcome them to death, etc. This happens in Spring Awakening in Those You've Known, my favorite song from that OBC recording. While it is cheesy to say, seeing the characters who have died come back in the end make it less painful that they have died (see the end of Titanic).
4) Much of the story is heartbreaking. The death of Fantine. Eponine's unrequited love of Marius. Javert's suicide. The revolution and the death of Marius' friends. Javert's inability to be forgiving of a man very worthy of it.
5) My favorite songs:
Empty Chairs at Empty Tables, sung by Marius
One Day More, sung by full Company
Javert's Suicide, sung by Javert
Who Am I, sung by Valjean
Do You Hear the People Sing, sung by the Students and in the Finale by the full Company
OK I have dorked out long enough on this subject.