Up till now the best I was getting was DTS from either Blu-Ray or HD-DVD (from a PS3) over optical. OTOH in my other system, I do get 5.1 uncompressed audio through DVD-Audio or SACD and it's outstanding even though it's hard to find content now.
Decided to upgrade the HT system and have gone for a Onkyo TX-SR576. It does HDMI 1.3 passthrough and processes Dolby Digital Plus but doesn't have on board Dolby True-HD or DTS Master HD decoders which is okay by me since the PS3 doesn't output these signals as bitstream anyway. It internally converts them to MLPCM which is then output over HDMI. The Onkyo can then convert these signals to up to 7.1 (though I have only 5.1 in the HT system - just can't find a way to place or get permission to place 2 more speakers!)
So when this beast is installed I will be uncompressed audio for the HT system which I am looking forward to.