Hi Murdock, thanks for plugging away with me on this...
My machine is a core/hybrid that I built about 10 months ago now. The spec is as follows:-Asus M4A87TD Evo AMD 870 (Socket AM3) DDR3 Motherboard
AMD Phenom II X2 Dual Core 555 3.20GHz Black Edition (Socket AM3)Asus GeForce GT 430 1024MB GDDR3 Low Profile PCI-Express Graphics Card
G.Skill RipJaw 4GB (2x2GB) DDR3 PC3-10666C8 1333MHz Dual Channel Kit
Akasa PaxPower 500W Ultra Quiet Power Supply
Seagate Barracuda 7200.11 1.5TB SATA-II 32MB Cache - OEM (ST31500341AS)
Samsung SH-B123L/BSBP 12x BluRay ROM DVDRW DL & RAM Lightscribe SATAII Optical Drive - OEM Black
Edimax EN-9260TX-E 10/100/1000 Gigabit PCI Express Network Card (EN-9260TX-E)
ThermalTake DH202 Black VJ80051N2Z with 7" Touch Screen Case
I actually posted the spec on the forum before I bought it all, and there were no issues raised with any of the hardware. As of this afternoon, I've basically already tried the things you suggested. I know my amp is fine with the dolby digital and DTS, because it works fine using the optical SPDIF output, and I can play audio from LMCE with this setting in the avwizard. I went back and tried the hdmi setting again, but said no to the other two in the avwizard, still not working.
Here is a list of my amixer scontents file as of now:-http://pastebin.com/FTMtj31x
I do have one question though, my Nvidia card is listed as card 1 in alsamixer, and the onboard as 0. Everywhere I see the settings for the audio, I see 0 selected, like in the multimedia settings on the kde desktop, and in the asound.conf files. Is this just something I'm reading wrong, or is it valid?
As I mentioned before, I have had it working through the kubuntu desktop, pre-mce install so I know it can work, but maybe this is irrelevant for LMCE??
(Also I can't replicate that again now, I tried so many fixes previously that I can't remember which one actually got it to work!)
Will keep digging!