I heartily agree on the audio quality of Patricia Barber's jazz recordings. I have all her CDs and love her work, but if you don't know her work, be aware that she's not for everybody. In comparison, Melody Gardot's recordings (which also have excellent sound) are much more mainstream, likely to appeal to just about anybody. Incidentally, Gardot has a new CD coming out in a few weeks. Another particularly well recorded female vocal jazz/easy listening CD in my collection is Jane Monheit's Taking a Chance on Love. She has quite a lovely voice.
For my money, the best female jazz vocalist of all time is Sarah Vaughan. I have two pricey JVC XRCD recordings by Sarah ("Crazy and Mixed Up" and "How Long Has This Been Going On"). Both are excellent. Although not pricey and not "hi res", there are two Vaughan CDs on the Roulette label ("Sarah + 2" and "After Hours") that are quite possibly her best work, and the sound quality is very good.
As for jazz that's all instrumental, I can recommend several CDs on the FIM (or LIM) label; though pricey, I don't think you can go wrong with anything on that label. The ones I have are "Jazz at the Pawnshop", four by the Tsuyoshi Yamamoto Trio ("Midnight Sugar", "Autumn in Seattle", "What a Wonderful Trio", and "Misty"), and "Super Triango". The last is Tango music (piano, accordian, and violin with cello added on a couple of tracks). I've always hated accordian, but on Super Triango I absolutely love it. The performance and sound quality on Super Triango is a revelation. The seventh FIM disc in my collection, which is both instrumental and vocal, is "Ella and Louis."
I don't spend nearly as much time listening to classical, but one that's been around for quite awhile and has always been very highly regarded is the solo piano "Nojima plays Liszt" on Reference Recordings. It was recently reissued as an HDCD, but I found no perceptible sonic difference between the original and the HDCD reissue.
