Hurleybird found an article over at Next-Gen that discusses the "40 greatest game design innovations." After a while it kind of reads like a list of normal gameplay mechanics, but they do go back and try to identify when each was first used. Wing Commander gets the nod for adaptive music that dynamically responds to changing situations. Each franchise seems to have gotten a single credit, or else other games in the series could be all over the article. You can find the full piece here. The Wing Commander bit is on page four.
Everyone recognizes the power of music to create a mood. In videogames, the trick is to change the music in response to game events, and of course the composer can’t know in advance when they might occur. One approach is simply to play a new track on demand, but the transition can be jarring if not done well. Another approach is layering—mixing harmonizing pieces of music together and changing their volumes in response to the needs of the game. Best-known early example: Wing Commander, 1990. Possible first use: Way Out for the Atari 800, 1982.