What an interesting, thought provoking question. With live music as the standard for me, here are my two:
Lyn Stanley - Pink Cadillac and Route 66 on 15ips RtR tape (London With A Twist, Live At Bernie’s). Stupidly expensive, but, SQ second to none IMHO.
Eric Clapton - Unplugged on MFSL Ultradisc One-Step, especially the Before You Accuse Me track. OK, there is some controversy about using a DSD file to make the lacquers. But, who cares when SQ is this good, outstanding.
I intend to work my way through the list of suggested tracks, thanks gladmo.