Another vote for the late 1950s/1960s Contemporary albums: Art Pepper Meets the Rhythm Section (1957), Art Pepper + Eleven: Modern Jazz Classics (1959), Gettin' Together! (1960), Intensity (1960) and Smack Up (1960), the Japanese release Art Pepper with Warne Marsh (1956), plus the Vanguard set - I agree with couw's assessment of Pepper's playing during the Vanguard dates.