(FORTUNE Magazine) – Let's hear it for Sumner Redstone. He may wear cheap-looking sports coats, have trouble sharing credit for his company's triumphs, and refuse to name a successor. But the 80-year-old CEO doesn't have to defer to anybody. He owns $8 billion of Viacom stock (market cap: $77 billion), including enough super-voting shares to control its board of directors, not to mention assets like MTV, CBS, Paramount Pictures, and Simon & Schuster. And Redstone--who recently married a woman half his age--is showing no signs of slowing down as a dealmaker. He's snapped up assets from debt-laden competitors like AOL (Comedy Central). Now he's eyeing Vivendi's Sci Fi Channel. But the most impressive thing Sumner has done this year is negotiate a deal to keep Viacom's respected COO Mel Karmazin--a guy with whom he has a famously tense relationship--from jumping ship (see No. 18). Investors swooned. Mel even went to Sumner's wedding. Now here's the question: Can they keep dodging divorce? --Devin Leonard