"City of Glass" (the Graettinger album) is a must. Also, "Easy Go," a compilation of early '50s sides, has some wonderful Art Pepper and Conte Candoli playing on great Gene Roland and Bill Russo charts.
As for the '40s stuff, I'd say the Classics CDs are the way to go, with IMO better sound than the Mosaic. I wouldn't worry about missing out on the alternates - they don't add much to the picture.