Sorry, can't choose!
Not even going to try eenie meanie miney mo either because if I did that and chose one that way, I'd instantly be able to come up with a reason why I did not like it as much as another one.
I thought maybe going with which one I thought Shannen did her strongest acting in, but I think she was consistent throughout her run. Then I thought maybe I'd go by which season had more favorite episodes, but that comes out fairly even on all as well.
I guess I'll go with the 1st season because that is when Brenda/Dylan became a couple. So there's my choice, but like I said before, I've already thought of something that makes the 2nd season better (Brenda/Dylan were a couple for mostly the whole season). I have a reason for liking each season that makes it equal to the others in my eyes. Oh well, I tried.
(I think this one is cute. In a way, it's like me trying to decide between the 4 seasons as well.)