For me, it's Autumn all over - especially that early autumn part where it's not summer but the weather is still nice but not uncomfortably hot. Then the leaves start turning amber and brown and everything looks so pretty and autumn/winter season clothes are just so much better too!
In Perth, where I live, Spring is the greatest season by far, over literally every other season that I have been in. It's usually 25C every day, cloudless skies and the water is a little warmer. Summer is nice as well but sometimes the heat is just death.
I love Spring. It's so beautiful, and I feel so warm and hot. I feel like I could hug everybody, and.. erm, I'm afraid, since the other thread, I must censor my dirty mind.
I am not 100% sure that I experience anything other than Winter and a less-snowy-Winter. ._. Well, there's that week of sunshine and warmth which is nice, I guess.
Winter! Seeing the landscape with a new snowy coat of paint always brings a smile to my face. Plus, nothing makes you feel more alive than having a nice hot beverage after coming in from the cold.
Autumn/Fall, definitely. The best things come with autumn - Halloween, Thanksgiving, peppermint mochas, fires in fireplaces, pumpkin cheesecake, comfort fooooood, boots, scarves and sweaters. There are few things I love more than seeing piles of leaves all over on the ground of all different colors. There's a feeling of the year winding down before the stress of Christmas and the new year where you just get to stuff your face, relax and enjoy yourself.
Fall is best because you get all of the good stuff about winter without freezing your smurfing ass off.