Tried my own original CD version of the game along with a patch that can let it run on XP on the XP installation on another HD on the same PC today (a Pentium Core2Duo 6300, 6GB RAM, Geforce GT440). Bump mapping and True colour textures work with this version, but it seems modern hardware has problems with the primary display mode you can choose from the options menu. With my graphics card, everything beyond the clipping range just is black, and there are graphical errors. Actually the nGlide version appears better apart from the missing bump mapping and lower framerate.
Sorry for wandering off the topic: The other thing I noticed is that there's EAX sound (with room reverb etc.) in the CD version of the game, but in the gog version it doesn't work, and the option to enable it also can't be changed in the gog version similar to the graphics. Has anyone noticed this as well?