I like my characters to have quirks or flaws. No one is perfect, so characters need to have something that sets them apart from the others.
One of my most recent reads, Landline by Rainbow Rowell (still need to write a review for this), has two flawed characters - Georgie and Neal. They have the best story - they love each other so much, but can't seem to communicate. They each make bad decisions, they don't talk about anything anymore and they seem to be pushing each other away. I love that they felt like real people with real problems, not just that perfect couple who happened upon a small bump in the road of their life. They are flawed and I adored them for it. I loved Rainbow Rowell's writing and if she will always serve us up such amazing characters then I will forever be a fan.