I think mine would probably be Esposito

Esposito is one Of my fave characters but I have to say that I love Lanie, for some reason she is Beckett's conscience! I pick Lanie!

I love Esposito too! (and Lanie is closely behind him) But I would have to say Ryan. He would be my next favorite character after Castle/Beckett. So yeah! : )

I think that's what makes this show so great! So many wonderful supporting actors - it's so hard to pick a favorite! :)

Yes indeed Spenser. Great cast to a Brilliant serie!

I love Ryan, i think he's cute :) and I like Lanie, I love her friendship with Kate in 4x20 :D

I love Ryan ,Esposito ,Lanie and Martha but my favorite out of these is Kevin Ryan <3