The container is pretty much part of the codec, as far as I'm concerned. If I'm making a Nero AVC, it's going into the mp4 container. If I'm using xvid with mp3, it's going into an avi. The same reasoning applies to most video codecs.
If I'm using Nero AVC, I'm almost certainly using a lower
audio bitrate than 128Kb/s (HE AAC). And, if I'm using Xvid, I just might be using a much higher bitrate than 128Kb/s (the original AC3 stream). If I'm using the Ogm container, I'll be using Ogg Vorbis audio which will give me a bit savings greater than the Ogg container itself over avi. But, adding these factors into a codec comparison is impractical.
So, I'm voting for dump the audio but consider the container. #2, I always vote for the loser, 'cause I vote 3rd party.
I can mentally factor in the effects of audio on bits I'll have left for video. I know if I go with HE AAC or Ogg over MP3, I can give the video more bits. And, if I keep the AC3 stream, the video will get less bits.