Probably not what everyone would consider sci-fi, but if you can find the abridged versions (*stay with me) read by Tony Robinson, the Discworld audiobooks are really enjoyable to listen to.

Good Audio Sci-Fi

  • Snow Crash
  • The Martian (more fictional science than sci-fi, but still excellent)
  • Ringworld series
  • Daemon
    • Freedom
  • Gateway
    • Beyond the Blue Event Horizon

*Unfortunately, the unabridged versions were read by Nigel Planer and Stephen Briggs and neither of them capture the characters in the same way Robison does.