Next time you come across a ogg file, use audacity (http://audacity.sourceforge.net/) along with LameMP3 codec (http://lame.sourceforge.net/index.php). This will allow you to convert the ogg files to MP3.
I’ve never had that much of a problem. Though I’ve only converted UT2004 and some random tracks.
For best results, I convert .ogg files to 44100 wavs first using ezcdda extractor, then I convert to .mp3s if I must.
Good examples are PREY, UNREAL 2, and HARRY POTTER series.
Bioscope