Hello people, I don't know if this is the proper place to show this, or if this is going to get any atention at all, but I wanted to sahre this thing I made, a model replacement of Dagoth Ur, here you can look at it:
http://www.nexusmods.com/morrowind/mods/43602
I'm not used to publicize my hobby stuff or participate in a modding community, but after I finished the model I wanted to see if I could put it in the game and see it moving, when I managed to barely achieve that I thought that maybe someone would enjoy having a higher poly/texture resolution Dagoth Ur model in replacing of the old one, and maybe I could receive information on how to do this kind of things (model replacement) properly, 'cause my knowledge in this matter is a bit poor and there are some problems, for instance:
- When you first meet Dagoth Ur he often holds a magic effect in his hand, but I think the particles don't look like they should in this mod, I really don't know what to do about it.
- When defeated in the first encounter his body is supposed to disappear with a fading effect, but in my mod his body just disappears abruptly. Again, I really don't know what to do about it.
- I know the .nif is a bit dirty, but I lack the knoledge to handle .nid files and Nifskope properly.
- I had to change the importing nif options in Blender to be able to import the original skeleton and mesh in a proper T-pose to work with, I know this isn't the best way to do this, but other options imports the whole thing in a Relax pose that is not good for adapting a new mesh to it. Again, I lack the knowledge to sort this out.
Those problems don't prevent this to be effective and functional in replacing the old mesh model, I hope you like it and sorry for my English.
Saludos.

Also, as Pherim suggested there, it is best to convert textures to DDS format. DDS compression that is best is DXT1 for textures with no transparency (alpha) used, and DXT5 is best for textures with transparency. Also always generate MIPMAPs for textures. Finally, using GIMP DDS plugin is not recommended for this, as Pherim recently found out that the MIPMAPs it creates are a bit weird. So as he recommends, Paint .NET is good, or I can recommend http://www.nexusmods.com/skyrim/mods/12801/?. It is posted on Skyrim Nexus, but works for all TES games, plus can batch-process whole folder. I hope this will help you a bit