I've been addicted to Winx Club since I first saw it on Nickelodeon. Ok, I'm 28, but so what? It is SUCH a relief to have a girl-led show that has action and adventure instead of just cutesy fluff. You know those kinds of "girl" shows, where there are no stakes and everything's sunshiney and happy? Well, Winx Club is the opposite of that, guys. There are menacing villains, like Valtor and the Wizards of the Black Circle. There are a lot of Nick stars who do the voices, too: Liz Gillies (aka Jade on Victorious) does the voice of Bloom's sister Daphne, and Ariana Grande (aka Cat on Victorious) does the voice of Diaspro. One thing to know is that every season has its own story, so you should try to watch the episodes in order, to understand what's going on.
Review of Winx Club
