As he happily would have told you at any point during his life, there is perhaps no single person more responsible for the look and attitude, if not the sound, of punk rock as it's been known for the past 30 years. Much of his sensibility, and thus the sensibility of generations of punk bands, stemmed from his other role, as co-owner of the London S&M boutique SEX. That aesthetic—chains and leather, not to mention the complicated power struggles and relationships with authority those things symbolize—has never really gone away.
Cynically, McLaren was also among the first to recognize the potential to cash in on people who wanted, desperately, to self-identify as "other"—his fingerprints are all over the lucrative modern-day mall-punk culture, which has thrived for exactly as long as people have been railing against it. Just as he'd always seemed to envision it.
It may seem strange to say someone will be missed because of their uncanny ability to manipulate people, but that's ok. It's true.