Conan just looks tired, like he doesn't know what tone to quite strike with The Tonight Show. Not that you can blame him, with Leno showboating him.
Fallon is what Conan used to be, younger, hipper, more spontaneous. Letterman is second. He's the same, but dependable. Craig Ferguson, 90% of the time I flip to him, it's just him sitting there by himself Not that you can blame him...