1. Crucible: Best quest for me, it has everything that this game can offer condensed in one: good fights, mazes, puzzles, riddles, traps, more mazes, nasty troll mobs (funny to get sleet storm'd above the maze when you don't have fom).
2: The pit: Similar to the above + Mario jump skills.
3: Monastery of the scorpion: more traps, nasty traps, which can be avoided with skill. Fights and a very nice end-fight where you can choose how to end it.
4: Rainbow in the dark: darkness fun, traps, rust monsters, lots of fights, puzzles.
5: What goes up: this one just feels too epic when you get to the glacier.
6: Stealer of souls: I love quest mechanics and background story behind it, all 4 maps + endfight are amusing. Flag is a bit annoying.
7: Into the deeps: Did it 3 times a day with the old epics, never got tired, was fun to figure out the strategy on an undergeared group and still get it done.
8: Ghola fan: annoying to get to the quest, but the quest itself is fun and well designed.
9. Haunted halls: see #1
10: Gianthold Tor: I get the epic feeling in this one too.
11: In the flesh: Bit of a challenge, need a brain to complete it, beholders and minflayers random attacks makes it very dangerous
Raids:
1: Tempest spine: A huge fortress with traps, enemies, maze, no map, a lot of optionals, and a very nice endfight that requires some brain.
2: Lord of blades: Was really challenging when it came out, needed lots of teamwork and coordination, has a lot of mechanics and required several different roles.
3: Deathwyrm: Would be perfect with 2-4 less mirror rooms.