Here's a handy list of downloads on the vault that alter your User Interface. Feel free to link more so I can add to the list. Before you install any of these it's recommended that you make a backup (simple copy paste) of the override directory/folder in NWN directory so if you don't like the new looks you can easily revert. I know a few that try the 'invisible' looking GUI hate it. It's just one of those things we either love or hate!
These overrides usually don't conflict with each other... but if you find yourself crashing a lot after installing them, you'd best revert and find the issue. With the ones I use however, I find no problem.
These first ones were made by
The Amethyst Dragon.Transparent Unobtrusive GUIIcons: (These go very well with the transparent UI)
New 1.69 IconsEmotes for 1.69Feat & Ability Icons: ColourisedClass Icons: ColourisedDungeon Master Icons: ColourisedRadial Icons: ColourisedSpell Icons: ColourisedImmunity IconsOther:
Hands/Feet (KuraiRyu)I have some more which I'll add, such as spell casting sounds which may not have been released on the vault (I got them via the nwn.bioware forums years ago when a guy was looking for testers).