Those are some great sites. Allmusicguide would be a good place to start as well which gives you a feel for how the Artist ended up doing what they did and a feel for where it went from there.

Once you decide on what you like, I recommend All Music Guide to Jazz: The Experts' Guide to the Best Jazz Recordings (a book). It has lots of artists in it with their works rated. So many CDs out there are reissue material. As an example I think Charlie Parker (although bop) has more "albums" to his credit than actual songs due to the infinite repackaging of the same songs.

The latest trend is for Greatest Hits for an artist. Unlike rock groups today, most jazz musicians of that time period jumped from label to label so a Greatest Hits compilation probably won't mean much.