You can't have just one Miles, but you should probably start with Kind of Blue. If that seems rather tame to you, go forward to the second quintet (Shorter/Hancock/Carter/Williams). My favorite is ESP. If Blue isn't traditional enough for you, go back to the first quintet (Coltrane/Garland/Chambers/Jones). Cookin' and Relaxin' are my faves.
As for Clapton, there is only one place to start: John Mayall's Bluesbreakers with Eric Clapton.
As for Clapton, there is only one place to start: John Mayall's Bluesbreakers with Eric Clapton.