The OpenGL Renderer by Chris Dohnal has worked flawlessly for me. Assuming the "Gold" version 226, the installation is as simple as replacing the OpenGLDrv.dll / OpenGLDrv.int with the updated ones. The old official renderer seems to work only on old systems, and is allegedly incomplete.
I have personally used OpenGlDrv2.1.0.6_Gold.zip and OldUnreal MultiMedia Patch 0.99 / 3.7.0.0.
The driver restores full contrast of all lights, which was lost in the official, accelerated renderers, improve responsiveness when starting and closing the game or switching resolution, and allow tweaking of standard quality settings (like anisotropy) from within the driver itself, instead of the video adapter's applet.
I've never played with the S3 Textures, and those would seem like a foreign "mod" to me. I find blocking in DXT compression blocking more irritating than smooth bilinear in close up, which is not that noticeable in Unreal because of Detail Textures.
OpenGL:
Direct3D, official:
Software:
Sorry, I've no access to Glide.
The general wisdom I follow is to use the oldest version that works, as that is likely to work on most systems. I have also on purpose avoided anything to do with Direct3D, since D3D games tend to 'break' after a couple h/w generations, which is disappointing (glquake works, d3dquake broken...).
With OpenGL, I have also resolved the issue I had earlier, where the screen border showed garbage with anti-aliasing.
Audio is solid on my system, even when the d3d appears to "hang" during alt tab, switching modes or quitting. Maybe adjusting the sampling rate of Galaxy.GalaxyAudioSubsystem in Unreal.ini would help. I run it at standard 48000 Hz.