When chilling at the house, this is a really relaxing song to listen to. Might not be "THE" main menu theme, but technically you probably spend a good amount of time at the Gates of Hell, so I like to think it counts for something.
Making a good title/menu track is real tricky and a bit of a catch 22 really. It's very tempting to have something really epic and extravagant, but if you play the game a lot you're going to be hearing it over and over and it will quickly wear out its welcome and lose all the impact. I think WoW's login music for each subsequent expansion suffer especially from this since they keep making these really loud and lavish overtures that I unfortunately just get sick of if I keep playing with the music on.
That said, I think the UT99 music strikes a good balance.