sby's loader for sure if you're looking for most features and possibilities. It doesn't have preloaded characters and dialogues. But it has the most comprehensive set of mods for allowing extra features and the cleanest file layout. Also includes plenty of useful documentation on how to use things and is fairly painless to get many other mods working with. Think of it as the best blank slate to load whatever dialogues or characters you want to use. My audio dialogue pack is basically sby's loader with a couple extra mods installed and an auto audio dialogue that plays like a movie preloaded onto it.
If you're looking for something that has a lot of preloaded dialogues that you can just select and play, and some extra features, try Dr. Zombi's loader pack.
