I wasn't too satisfied with the gamestartup.mp3 MusicallyInspired made for Opposing Force (I'm not a fan of the song or the ones similiar to it) so I went and dug up
this old module I had laying around and made my own. The song itself seems to be a breakbeat version of "Name" (track 15 on your Opposing Force CD). I cut out most of it, snipping it cleanly off where the beat builds up about 1 and a half minute in, c+ping the intro fade-in and fading out so it loops flawlessly. It might be a bit long for a menu song (though I've seen longer) but I hope you like it anyway.
link:
http://www.megaupload.com/?d=W9Z4W43M