Great idea for a thread. I hope you get many takers.
Etta James - I like her 50s and 60s singles the best, so I really like her Best of collection. I also really like her mid 80s record "Seven Year Itch".
Ella Fitzgerald - My favorite recording of Ella is her 40th birthday concert in Rome ("Ella in Rome"). She is at the height of her powers here, accompanied by the nonpareil Oscar Peterson trio. The sonics are very good to dazzling. "I Loves You Porgy" is my favorite Ella ever.
Sarah Vaughn - My favorite Sarah record is "No Count Sarah", a recording she did with the Count Basie orchestra w/o Basie. This record shows off Sarah's jazz chops beautifully and puts her at the top of the bebop vocalists. Her work on Horace Silver's "Doodlin'" is as good as any jazz she ever did. Sonics are 60s studio cool (a bit too much reverb) but fine.
Billy Holliday - Much of the Billy Holiday that I have is on vinyl that is older than I am, so I don't know in what form it is currently available. My favorite stuff is the pre-war work she did with Lester Young. This stuff is constantly being repackaged. "Lady in Satin" is an astonishing piece of her later work, and is an essential document. Sonics are a non-issue here.