Thanks - should help a bit, but it'll still be difficult to match them up. I tried using the track lengths but the music extracted directly from the game seems to vary slightly in length from the CD versions. My Hazardous Environments is 1:22 in length and the CD version is 1:25 in length. So my idea was... I only have the music, you have the titles, so if you play a song and remember where it played in game and tell me, I'll know which song it is. If so, that's my best chance of matching up the tracks to song titles.
Anyway, thanks for the reply. :)
Have you tried using the Musicbrainz (http://musicbrainz.org) program to see if it can match up the music to the titles? If that doesn't work... I'd go with just finding it online and downloading it. Might be easier. :)
If you love music, then maybe you should just buy Audiosurf? ;) Great game for 9 bucks and you get the whole soundtrack from HL, HL2, HL2: Episodes One and Two, Team Fortress 2 and Portal. :D (HL2 soundtrack isn't tagged tho...)