So, to avoid this just being a topic for me to plug a mod I like, let's see which mod you are most proud of, provide a link if you want
EDIT: Damn, that was supposed to be "Which mod..." not "What mod..."
EDIT: Actually it might be a toss up between the one I linked and http://www.fallout3nexus.com/downloads/file.php?id=7880. I wrote a fiarly detailed backstory for the house on the computer that I was really pleased with, but unfortunately very few people noticed it or didn't download it, that's one mod I really want to get attention because I feel it adds a nice little bit of flavour text to the game and to Andale. It also works with the main quest of that area as it's basically just another clue to what's going on.