1. Icecrown Citadel. (great music, great lore, great fights, great scenery)
2. Ulduar. (pretty much same as abve)
3. Karazhan. (just all around neat)
4. Firelands. (Great environment, music, cool boss fights)
5. Throne of Thunder (would have been great if it was just a little less linear)
"Do not look down, my friend. Even in the darkest of times, there is always hope... Hope for a better day, hope for a new dawn... Or just hope for a good breakfast. You start small, then see what you can get." ~ Covetous Shen
Good days.. Especially BWL, most epic raid ever, right next to where I was 15 manning or later 5 manning my instances for a drop or 2.
For me, Wow is all about the Blackrock mountain, I love that place, the way BRD lies at the bottom and is so intricate is sublime. There has never been another BRD. Why are all the best instances in vanilla. What happened after that? I liked the instances in TBC also but by the time we hit WOTLK the instances were very poor and unimaginative. Nowadays they are all flashy but no substance. You know what is Blizzard magic? The grim guzzler bar. It's so menacing. I think dwarves are evil. And I'm horde. Well of course I am.
Anyways my list probably will never change unfortunately as I don't see great raids any more, even thought Ulduar was poor.