Steve Jobs & Steve Wozniak (colleagues; commercial partners) The proverbial "two Steves in a garage" who founded Apple Computer, Inc. (with assistance from Mike Markkula)
Mad dogs & Englishmen (complementary; title) Noel Coward song title, referring to creatures that "go out in the mid-day sun" in tropical climes; also motion picture title, name of singing group, name of advertising agency.
Motherhood & apple pie (complementary) The two primary undisputed American values
Mutt & Jeff (fictional; companions; comic strip) Creations of Harry Conway "Bud" Fisher; it was the first well-known daily comic strip. Hence also proverbial for any tall-short pair of men.
Nature or nuture (opposing)
Nuts & bolts (complementary)
Oranges and lemons (complementary) (Nursery rhyme)
