Wow, I'm very happy to know your opinions and I thank you all! I wish I could have read them sooner, but unfortunately I've been too busy lately. So, this will be a long post, I warn you
Stiggie, I totally agree with you about Tifa (including your opinion about strenght and femininity), except for when you say she's underappreciated. On the contrary, I think that she's often idolized too much. Plus, you shouldn't allow people's comment to ruin your appreciation for Aerith, since she's such a well written character - just an advice.
Makoeyes987, you 've won. Truly. "He goes from a cocky jerkass to a vegetable to a badass yet awkward hero with a heart." is definitely the best definition for Cloud. I love it, ahah!
I also find very interesting kathy202' s analysis of Aerith!
So, my first favorite character is Tifa. It's very easy to empathize with her, since she has a very human personality, made by light and darkness, by strenght and fragility. I love her main theme, her job at Seventh Heaven, and the atmosphere of the pub increases my image of her as a precious friend, a mature sister, a comforting person, calm and sweet. Her voice in the remake reinforces my ideas so well.
Tifa has a sad past, but yet she tries to smile and put her problems aside to help her friends. She needs protection, but she's also tough and can deal danger by herself. Plus, her combat style is one of my favorite and the best in the remake. A girl fighting with her fists is wonderful for me, especially because I love boxe.
My second favorite character is Aerith. Her story and her attitude are very intriguing and charming. I believe that she's one of the most memorable character in the entire franchise (and not due to Sephiroth's actions). Aerith is a very humble girl despite being in possess of a rare power, and I admire her because she hears the planet suffering, but still she's optimistic and cheerful. What I like about her the most is that she is in love with life and nature, she's really a model to follow, and a medicine for those who have lost interest in the world's beauty. She's delicate, but yet, just as Tifa, she can protect herself and her loved ones. She's such an unpredictable character, capable of reminding me a lively kid and a charming woman at the same time. Her spontaneity and grace let her earn other points too. Aerith is particular character really memorable. Her main theme is of one the best soundtracks ever made, it tastes of victory, with a mixture of melancholy and comfort in it, like a caress of the earth. I really like her a lot and I wish I could've seen more moments between her and Tifa. Lastly, even if Tifa is my favorite character over all, I'm definitely pro Cloud/Aerith. They make quite the couple, one of the best in the videogames' history.
My third choice would be between Nanaki (yes, it will always be Nanaki for me) and Cloud. I've been so interested in Nanaki since the very beginning, when I saw him trapped in Hojo's facility and I realized he was able to talk. His story, his design, his combat style... I love everything about him!
He acts as a serious, cool character, despite being relatively young, but sometimes this contrast shows up and donates more shades to his personality. Besides, he's wonderful with Barret, they form a surprisingly interesting comic duo.
What I like a lot about Cloud is that is not a perfect, invincible hero. He's just a common guy with lots of insecurities, who travels to find his true self.
Okay, I'll stop here for now.