Late Night with Jimmy Fallon“I love that guy,” Tonight Show host Jimmy Fallon effused tonight of David Letterman — one night after Letterman announced he would retire next year. “It’s hard to imagine late-night TV without him, ’cause he revolutionized it. He made it what it is today. And, after I heard the news, I kind of started thinking about reasons why Letterman is retiring. … If you want, I could just read my Top 10.” Here’s the clip: