Any other recommendations for mods that will improve my enjoyment of what is supposed to be one of the best FPS-RPGs ever made would be greatly appreciated.
I'd consider the ReBirth (
http://www.fileplanet.com/125428/120000/fileinfo/System-Shock-Rebirth-Beta-1) mod equally essential. It replaces most of the character models in the game with more detailed versions and more high res textures. Does a lot to improve the atmosphere in the game even further, in my opinion.
It's a bit tricky to install properly though so make sure you follow the instructions carefully. Otherwise you might end up with all the characters in the game being invisible, I noticed. :)