Some great suggestions.
I would echo the suggestion you look into the solo albums by the other members on Kind of Blue. Also - if you don't have KOB in mono - I would highly recommend you try to find a copy. The best sounding stereo CD version of KOB is the new 2-CD Legacy Edition.
Bill Evans (piano player) has some great stuff out there. Look at "Sunday At The Village Vanguard", "Portrait In Jazz", "Waltz For Debby", "Everybody Digs Bill Evans" and "Explorations". IMHO, you can never go wrong with Bill Evans.
John Coltrane has many great recordings for many labels. Coming from KOB, I would recommend "Ballads", John Coltrane & Johnny Hartman", "Coltrane", "Standard Coltrane", "Blue Train", "Lush Life" and "Soultrane".
Cannonball also had some great releases, in particular I would recommend "Something Else", "Know What I Mean? feat Bill Evans" and "Live In San Francisco".
If you want to pursue Miles, I highly recommend "Cookin'", "Steamin'", "Walkin", "Workin'", "Miles Davis and The Modern Jazz Giants", "The New Miles Davis Quintet", "Bag's Groove", "Relaxin'", Miles Ahead (Both Mono & Stereo versions are essential). All of his work with Gil Evans is fantastic as well. There is a rare album called "Blue Haze" from 1953 which is also quite good yet many people have not heard it.
Other great jazz albums you may like coming from Kind of Blue are the following:
Sonny Rollins - Saxophone Colossus
Sonny Rollins - Tenor Madness
Sonny Rollins - Plus 4
Sonny Rollins - Way Out West
Thelonious Monk - Brilliant Corners
Ben Webster - At The Renaissance
Chet Baker - Chet
Gene Ammons - Boss Tenor
Thelonious Monk & John Coltrane
Coleman Hawkins - Night Hawk
Kenny Burrell And John Coltrane - Kenny Burrell & John Coltrane
Kenny Dorham - Quiet Kenny
Johnny Griffin - The Little Giant
That should keep you busy and content for a long time.
Most of these can still be found cheaply. Buy the OJC versions mastered at Fantasy Studios and DO NOT BUY THE EUROPEAN RELEASES!!!!!!. Most can be had for under $10.