Vicky or Cristina?
As a big fan of Woody Allen, I believe that Vicky Cristina Barcelona is one of his best movies. Specially after he changed his way of movie-making since Melinda&Melinda and Match Point. He is the best of telling stories about people and relationships and his movies' characters are real. They think and act like ordinary people and this makes Allen's works more important than the others'.
Vicky... is about our ambition to have different relationships. There's a fact that nobody is satisfied of what he/she has, all of us like to have something we don't have. In relationships, it happens a lot. When you're with someone, you always think about other possibilities, and depends on your manner, it can make you a successful person in romance-relations or not. In the movie, Cristina is so curious and likes to experience different and new situations, but Vicky is totally opposite of her best friend. She is engaged to marry her fiance, who seems to be a ideal match. But in their summer trip to Spain, they meet a painter who ask both of them to date. Cristina likes the idea but Vicky doesn't...
I don't want to retell the story, you should watch it if you haven't yet, but the most important part of the movie is its end, while Vicky and Cristina are going back to NY, Vicky is with his man and with a fear of her marriage's future, but Cristina is looking for new men... but she stays alone at the end.
There's no way to say which one is better.