I am at the system that I had the sound problems with after updating Gutsy previously. I am sure your system likely has a different sound card but maybe when you updated you had a similar thing happen. The file is /etc/modprobe.d/alsa-base
This is the line that was incorrect. Once commented out sound worked again. Notice all the additional model info and the two model=
options snd-hda-intel model=basicoptions snd-card-0 enable=1 index=0 model=basic
This was the correct line for my system.
options snd-hda-intel enable=1 index=0 model=basic
Hope this helps, let us know how it goes. If it is happening that Gutsy is adding the additional line to the alsa-base file breaking sound on some systems then I hope they have it resolved before final release-- I think that is suppose to be Friday.