I love em all, I was always fascinated by people that could do impressions since I was a little kid, which is why Jay is one of my favorites. But after listening to him a lot I have to say his Barry Katz is my favorite. Just because he knows him so well, and you can see he has such an ear for all of Barry's inflections & tonalities. Plus I love how he'll just start doing "Barry" for someone in studio that has no idea who Jay is supposed to be, that's my favorite. Like when Jim Norton was on over the summer, and Jay did the classic "Do you wanna do in a show in Japan" set up that he does, it was like a 4 minute piece and then he hits Jimmy with the punchline: "Do ya know how to fly a Leer jet." Jimmy was going with it the whole time, and then he goes "Who is that supposed to be?" That made me laugh so f*cking hard, it was one of my favorite moments of the year on any podcast. (I listen to about 10 different shows/comics)
2nd is Eddie Vedder.