You know, that epic music you hear when you get to the log in screen 
Which expansion had the best music and why?
For me I think it would have to be Wrath of the Lich King. That was when I got really into wow and that music to this day brings back years of memories any time I hear it
I agree the Wrath music was quite good, though the punctuation with the dragon roar (Sindragosa I think) was always kind of jarring and annoying (especially if you had headphones on and made the mistake of leaving the game in background and got logged out).
I think Burning Legion’s (TBC) music was also pretty iconic and great though, it kind of beckons you. Wrath just had that extra umph though and it might be because the intro song was forever associated with that legendary opening cinematic of Arthas plunging Frostmourne into the ice and well the whole epic expansion in my mind.
certain MoP tracks that played at the log in screen were amazing.
Wod was one of the worst expansions but the log in screen was awesome
I liked wotlk and tbc ones. TBC most nostalgic login for me and wotlk up there too
vanilla not an expansion but the login and music is the best.
The deathwing cata login one was oddly proportioned just looked squished on the stormwind pillars and the music was chaotic but messy melody.
Legion login music was nice specifically the climactic part of the song but didn’t like the goofy npc on screen
Bfa and SL… haha no comment.
WOD haves sum good music …
Like this?
Answer: Burning Crusade 
I love how it incorporates the Black Temple/Eversong Woods music.
The bit starting at 2:20 and building all the way to the end is just 
you’re right about tbc. so good. so epic. life was simple.
I loved the BfA soundtrack. It got me pumped. Too bad the story was lackluster. The less said about Sadfang and his jail house interludes with Anduin, the better.
WoD, MoP, and BfA are my faves.
Dragonflight hands down
There are a few songs in particular that I really enjoy, but I usually have to cherry pick them. Normally I play with sound off.
1.) Arthas my Son
2.) Anduin’s theme
3.) The Isles Awaken
If we’re specifically talking about login screen music, then I guess I like Dragonflight the most because eventually it starts using the song you hear during dragon racing courses.
i started playing in cata so it and mop are prob the most nostalgic for me
after listening to them all, think tbc has the most oomph, tho rlly liked bfa (didnt play) and wod
overall soundtrack though, wotlk has some of the best wow music period
Frankly I can’t remember them distinctly enough. I think some of my favorites were in some of my least favorite expansions too.
Wrath is just…soooooo overrated to me and I’m just sick of it being brought up now. The music at the time sure. But now, its been outdone. BFA to me is better. Boralus alone trumps anything WotLK did, except maybe one or two songs.
I really liked Warlords’ music. BFA was really good too.
I liked Warlord of Draenor’s theme song.
Mist of Pandaria’s is magical for me, there is a lot of nostalgia tied to it (I started playing wow in 5.4 Mist).
Vanilla’s intro music is pretty dope as well.
my money on on wrath
They all have great things about them, and I sometimes even listen to all of them in a row… If I had to choose one, though – Cataclysm. It’s when I started, and between the epic overture choir at the leitmotif, the melancholic Invincible mashed in, the theme of Gilneas, and the glorious ending… It’s probably my favourite theme in general.
Best theme song is WoD. All other answers are up for debate, but are still wrong.
I’d feel pretty safe saying WLK. I tend to forget most of them. Or at least forget which expansion the tune came from. WLK is the only one I can both recall in my mind right away, and know which expansion it’s from. Very unique and evocative.