A fantastic site I've stumbled upon lately is the Airmen of Note Archive. You don't get traditional big bands sounding consistently better than them.
They have an extensive audio archive for download with a small fee to support the bandwidth of the site. It seems a typically governmental thing to do to create amazing recordings and leave them to languish, and thankfully this site has dug them all up.
Clicking on the links to download all those MP3's isn't a very Linux user type thing to do. In that vein I've put a directory hierarchy filled with links to the albums and the album cover in airmen-download.tar.gz. Pay on the site for a user name, write a few scripts and you should be ready to go (feel free to mail me if you have no idea what to do). The original Python scripts I used to extract it all are available there too.
If you like Jazz, spend the $20 and get this fantastic collection. Although it's not all my taste, mostly because at times it feels a bit cheesy, it's a mine worth exploring for the fairly fairly frequent nuggets of solid gold.