1. Gustaberg.
https://www.youtube.com/watch?v=K0rYk83Rt0A
This was my first experience with MMORPGS other than PSO and I remember being confused as to what I was actually supposed to be doing, there was no guiding hand to tell you exactly what to do and where to go as there had always been with other games. I was just put into this massive area to go explore and level up on my own, so I did just that. For days I was just roaming around and killing things here with my hammer, loved finding the hill area with new monsters, the lighthouse you could go inside and the steam area with crabs. Gustaberg was all I knew of FFXI (I went in pretty much blind) and I was killing monsters for gil and buying spells and things, I literally had no idea there was more to the game than this at the time.
Then someone started talking to me in say after I gave them a cure and he told me I had to explore Konschat Highlands, because he had seen a "big white alien building" there that I had to see. That's when I found out there was more to the game than where I was.
The Gusta theme always has the most emotional impact on me, when I hear it randomly somewhere out of the game.
2. Selbina.
https://www.youtube.com/watch?v=oiGxNFlOO5k
While exploring in Konschat and looking at the "big white alien building" on my whm I got a tell asking me to come join a party, they were so desperate for a healer they came and guided me there (they also refused to take no for an answer). After the party broke up, I got another invite right away and again they dragged me further into the dunes. I remember after that party ended wanting to go back to Bastok for spells but having no map and no idea how to get back (I didn't know about deathwarp at the time), so I wandered around in the blinding white sand dunes totally lost for hours. Till I found Selbina, the music was so upbeat and welcoming and I remember being so happy I had found a town. I used Selbina as a base and kept trying to find my way back to konschat, retracing my steps back when I felt I was getting lost again.
The music had more impact because the previous areas had no music at all.
3. Fighters of the Crystal (crystal warriors)
YouTube Video Placeholder
Cover version.
This was my first endgame type group content and it was the most epic thing I had seen in any game, I leveled BLM just for this. The music is cool, the cut-scenes were amazing to hype you up. We did it with 16 BLM a WHM and a big Galka PLD, I remember being amazed he could hold these beasts all on his own without dropping when they could one shot most of us (looking back he used invincible but I didn't know that at the time). BLMs were getting one shot right and left but we took them down, and we were all so happy at the end and went together in this big huddle of blms to get our earrings.
4.Promivion
https://www.youtube.com/watch?v=jD2cQZmeaFc
I did Promivions with 5 long time real life friends, it felt like some epic adventure we were all going into. We leveled specific jobs, got the special level cap gear and we talked about these fights for weeks, it was a huge deal and literally did feel like we were going on some real life adventure or something. The darkness, the weird enemies, the totally alien landscape all made this all the more epic of an adventure, and the spooky and mysterious music fit everything so perfectly.
5. Sea
https://www.youtube.com/watch?v=d09ElJAdSlg
These missions were so incredibly difficult I really felt I was never going to finish them and it took a long long time, I did the first ones with friends but a few had to quit due to work. Then I had joined a static with my LS but there was some drama later on and the static fell apart. After that I had to do them in pugs and was so difficult to find groups because I had waited to do them till 9-12 months+ after cop launch (rl friends could not play as much and it slowed progress right down). I remember logging in and just sitting in lower Jeuno waiting all day, fruitlessly most days cause I either didn't have the job they wanted or there were few shouts cause most had done them. I wish we had /yell back then, I could never leave LJ.
The amazing music, the insanely different look of the zone and the relief of finally completing these missions to that point all made it a very memorable moment. I left the game running all night to listen to the music in bed.