I've been waiting for weeks to have time to answer to this thread because I know it's going to be a novel so here we go and here's my own personal favorites!
My overall fav episodeI bet no one’s surprised that my favorite episode of all the time is Hallowinx because I love horror stuff.

The Silent Villa house is AMAZING, the music, the costumes, pumpkins, fog and the mysterious atmosphere. You really can’t see what’s coming because the whole set up makes you wonder what’s real and what’s not. And I love the storyline of the sisters and I’m happy to see Jolly in the spotlight.
Then about my other favs of the 2nd season I also love the episodes 17 and 18 of the season 2: Twinning with the witches and In the heart of Cloudtower. I’m a huge fan of Cloudtower, Griffin, Zarathustra, Ediltrude and well… witches so it’s a dream come true to have episodes which are focused on these characters so you can get to know them, witchcraft lessons and Cloudtower as a building better (I know Cloudtower is a living creature but I mean that you can see new places, new classrooms, Griffin’s spa etc). And people getting stuck inside of the walls was creepy (in a good way!) And don’t forget Stella’s iconic witchy outfits!!
Lol it’s so hard to choose just a couple of episodes since the 2nd season is my ultimate favorite but I really love the episodes 19-26 since I love the storyline of Winxs getting Charmix, Wildland, Dark Bloom and all of the adventures and of course the season finale in the Darkar’s castle. And because I’m obsessed with Darkar’s castle, I also love the episodes 1-6. Winxs and the specialists exploring the castle, the introduction of Layla and the pixies, super cool prisons and new monsters, Downland and Amentia (she’s irritating but I still like her because of her strong will and confidence), finding new archives of Alfea and getting to know new places and characters in our beloved magical dimension. And the scene of Trixs in the monastery is so hilarious and has a great dialogue!
Ohh and The Show must go on episode always makes me cry!!

And it’s hilarious to see Griffin dancing in the audience and how amused Faragonda and Saladin are because of that.
Well these were my favorites from the 2nd season and I haven’t talked about the other seasons yet…
The 1st season favsThe Fall of Magix. As a kid I was obsessed with the scene of Trixs attacking Cloudtower and beating all of the teachers so easily.

I’m really not a sadist but I was so amused when Ediltrude and Zarathustra were hit through the windows and Griffin got stuck with the ice. The Trix were just so rebellious. And their monster army was so cool.
I also love the episodes 20-26 because I love the action and fights against the monster army, Winxs and guys exploring the Cloudtower, Riven facing what he’s done, Winxs exploring Domino and meeting Daphne (ohhh it always makes me cry…) and the final battle. The whole storyline about Bloom losing her powers when losing herself, and getting them back, is so symbolic for me and makes me so emotional.

And I love Domino and all of its mysteries and magical whispers of history.
Also I find the 18th episode, The Font of Dragon Fire, super interesting because of the revelations of Bloom’s past. It’s also super dramatic and has epic battles.
Miss Magix is also one of my favorites because it’s so funny!
And the episodes 1-6 will always have a warm place in my heart. I started watching Winx Club in the middle of the end of the 1st season and the beginning of the 2nd season so it took me so much time to find the dvds with the first episodes - I had watched Winx for a while without knowing how everything began! And when I FINALLY got to see the first episodes I was so mesmerized! Bloom meeting Stella and finding her powers and then getting to know Alfea,the other Winx girls, Magix, the Trix… Everything is so new, fresh and unique! Also I love the Black Mud Swamp and when the girls explore Cloudtower again. There’re so many mystical places in Magix!
The 3rd season My favs are the episodes 10-11, Alfea Under Siege and A Trap for Fairies, because of the hypnotized witches (I find hypnotizing very cool, that’s why I find Dark Bloom so fascinating too) and well… Cloudtower. How surprising!
My other favs are also 22-23, The Red Tower and The Crystal Labyrinth. As someone mentioned before, the music is amazing. And seeing the first magical creatures of the whole universe, that’s something really special. And the sacrifices the Winx girls need to make are breath-taking. Stella’s faceless face still creeps me out.
The 4th season I love the first episode because of the nostalgy of returning to Alfea after graduation, the new unknown enemies and the scene of Bloom seeing pictures of all of the previous villains on the wall. Even though I already knew them, the picture of Darkar creeped me out (and that’s why I love Darkar, he’s actually the most scary enemy the Winxs have defeated imo!) And all of the helplessness and confusion, when the Winxs girls can’t do anything - it changes the whole perspective of being a freshly graduated guardian fairy.
Also the episode 16, A virtual world, is cool because we get to see Gardenia Park! And how Timmy says they’ve been too focused on the computer so Duman got to escape. Like, I feel you, I would’ve made the same mistake.
So, here’s a short summarization: if there’re Cloudtower, Darkar’s castle, “dead” Domino or other dark and mysterious stuff, I’m in. And additional humour is accepted too.
