Memoria... For the music and also, how it was made. It was such a strange Place. Place of Memories... My fav. Final Dungeon. The music was touching.

Second comes Ultimecia's Castle. That place looked so mysterious what with the full moon shining above it, fighting the guardians... ANd the music rocks, too.

Yeah, these two. I like outer-spacish dungeons as well, such as the Final Floors of the Void (FF V) and Dark World (FF III). The last floors of Pandaemonium were cool as well.