For Sarah Vaughan try anything on the Pablo label (Ellington Songbooks, Copacabana, etc.) and stay away from her Roulette label material (more pop than jazz, but others may disagree). Also look out for her version of "September Song" with Clifford Brown, it's on several compilations.
For Ella Fitzgerald any of the Songbooks (Gershwin, Ellington, Rogers/Hart etc.) on Verve are great. "Let's Do It" with Louis Armstrong is also very good, as is "Clap Hands, Here Comes Charley".
Verve also has a multi-disc set featuring both Sarah and Ella in their 'Round Midnight series.
For Ella Fitzgerald any of the Songbooks (Gershwin, Ellington, Rogers/Hart etc.) on Verve are great. "Let's Do It" with Louis Armstrong is also very good, as is "Clap Hands, Here Comes Charley".
Verve also has a multi-disc set featuring both Sarah and Ella in their 'Round Midnight series.