culex-
Bump your gamma up around .5 before you enter the game(in display properties), that will take care of the brightness issue.
"Unless that Loki patch does wonders...?"
It certainly does, but unfortunately not for brightness issues. It enables you to use the S3TC textures on the second UT CD which significantly improves the visual quality of the game. There are some screenshots up in both the articles linked above but even those don't do it justice. You have to play it to appreciate it.