By Ken Tucker
Updated May 30, 2009 at 08:54 AM EDT

Jay Leno was gracious and funny during his final night as host of The Tonight Show. His main guest was the program’s new host starting Monday, Conan O’Brien. Seeing them together, the difference in comedy styles and sensibilities was striking. Where Leno is straightforward and old-fashioned in going for the big, topical guffaw (one major reason he commands the time period’s largest audience), O’Brien is more sly, ironic, and self-deprecating (qualities he shares with his time-period competition, David Letterman — hmmm, a possible problem for Conan?).

This night, however, it was just interesting to see Leno and O’Brien interact — or rather, not interact. There wasn’t much chemistry between the two men. O’Brien came out with some clever material about moving to California and the new studio from which he’ll do the Tonight Show. Leno looked on, smiling politely.

At one point, an audience member yelled out, “Conan rocks!” Leno said, “I agree. Conan rocks.”

In some ways, it was a typical Tonight Show. In his final late-night monologue, Leno went out with jokes that characterized his run. The man who brought us The Dancing Itos yukked this night, “I was cleaning out my office today, and I find O.J.’s knife! I had it the whole time! How could I be so stupid!” Ooof. Taking a jab at NBC’s current low prime-time ratings, he referred to his future 10 p.m. time slot as “a secluded spot where no one can find me.”

But toward the end, a different Leno was on display. Instead of the mighty joke-machine he prides himself on being, Leno allowed some nice, non-sappy sentiment to fill his final moments. He talked about how some staffers had met, married, and had children during his Tonight Show tenure… and then brought those offspring onstage. Sixty-eight young people of varying ages, smiling and waving.

It was a very sweet, low-key, and sincere way to end his version of The Tonight Show. And come Monday, we’ll see what Conan does with the job.

Did you watch? Will you follow Jay to 10 p.m.? Will you watch Conan’s Tonight Show?