Just do "HDMI Auto" and leave it at that. I don't think it uses 3/4 of them anyways, but if auto selects them then the receiver should handle them.

However, if you don't have 7.1 then I would unselect all of those - unless you can verify that your receiver will correctly reprocess 7.1 LPCM correctly to 5.1.

Otherwise, if you only allow 5.1 LPCM output and the PS3 plays a 7.1 track, it will correctly route the extra rear channels into the others.

The PS3 will *always* output BD high resolution tracks as LPCM. Make sure you have HDMI set to PCM output and not bitstream, otherwise it'll be reprocessing any uncompressed tracks into compressed.