A friend of mine gave someone who is a rabid Beatles fan a Butcher "Yesterday and Today" (used condition). He gave me the Mobile Fidelity Beatles Box and the Mobile Fidelity Rolling Stones Box. He also gave me a Marvin Gaye One Step. i think the two big box sets are worth something. I also have the Classic Records reissues of Led Zeppelin, but they are in open and used (by me) condition.
But, some of the records I particularly prize include stuff found in the $1 bin at a used record store. I found a copy of the first ever recording of Ramirez's "Missa Criolla" on Argentine Philips. Ramirez is Argentinian and the "Missa Criolla" is the first approved Catholic mass music in the vernacular, so it is historically significant. The version by Los Frontieros that I have is a terrific version of this mass.