I use the term "modern" loosely. I have a P4 3ghz, and a Radeon 9800XT. I'm not familiar with a few of the optimization settings, will these have any positive, noticeable effect on the graphics for me:
"Enable poly gap fixing"
"Enable mipmap sharpening"
"Enable single-pass multi-texturing"
I would just experiment, but I'm worried some might be features exclusive to 90s era video cards, and could cause some errors for me.
If anyone knows the best settings, please share your info, thanks!

Enable triple buffering too.
Leave "Optimised surfaces" off, I get hair-line artefacts on the HUD when its enabled. Someone in another thread said something about the counters (ie health, ammo) not be updated fast enough with it disabled, but that's just bollocks.

On mine I got everything enabled except poly gap fixing and it works fine.