Among many classics and favorites, many on vinyl, these are several that I think are both great musically and sound great on CD:
* Stan Getz -- Big Band Bossnova: This is awesome, one of the coolest sounding CDs I own.
* The John Coltrane Anthology: There's so much Coltrane out there, not all of it as well recorded and much of it better on vinyl, but this is a very good CD entry. And if you don't own any John Coltrane, well, enough said.
* Ella Fitzgerald & Louis Armstrong (that's the title), from Verve Compact Jazz series: Someone else mentioned this and let me second it. Who knows how it was recorded, but whatever it is, something about the register and interplay of their voices makes this a fantastic sounding CD, and the music is wonderful -- which was not always true of Louis Armtrong by this point in his career.
* Ella Fitzgerald, The Cole Porter Songbook, Vol. 2: An obvious choice but I had to mention it. This doesn't sound as good recording-wise as the Ella & Louis CD, but it's so great. We listen to it a lot.
Leaving out many favorites unknown to me on CD, but these are classics.
Birdman
