Point of View is as much a part of the experience of the book as those 3-D glasses are at a 3-D movie.
I can't imagine reading the Sword Dancer books and not having it in Tiger's POV. I wanted to know more about Del. I wanted to read what she was thinking, not just gauging her by what he saw her do. But that was part of the charm that kept me coming back, too. Yanno?
The Persephone Alcmedi series is all 1st person POV, her POV...until book 5. Then I started letting y'all into the heads of other characters. Specifically Johnny. I couldn't tell his tale without letting you in there a little bit. But it was 3rd person. When I'm able to get through the rest of the story arc and get to the last book, we'll even peek into Menessos's head. But I don't want to spend a lot of time there. It's a scary place.
The book I've been working on lately (and just wrapped...whew!) was all 3rd person. Maybe after a series with so much 1st person, I wanted something different. I'm sure that had some influence on it. But mostly, that is the only way the story could get told and, in the end, you must serve the story.
Can you think of a story in 1st person that might have been better in 3rd?
Can you think of a story in 3rd person that might have been better in 1st?
But what's really more important than 1st or 3rd is WHOSE POV you choose. Who has something to say that will get your reader engaged in the story? Who has the most interesting voice? Who has the most to gain? The most to lose? Who has already lost everything?
Think about this: Star Wars. (I know. You're sooo surprised, right?) Classic tale of the hero overcoming an enemy and saving lots of people in the process. Yay!
Then we get prequels. We see this adorable young Anakin...watch him grow up, love, and get manipulated by the worst dude in the galaxy, and remade, literally, a la Frankenstein, into the Bad Guy from Star Wars. But now we know too much. He's not the Bad Guy from Star Wars anymore. He's that poor kid that got mind-f**ked and, oh Obi Wan...why couldn't you see it and stop it and be the hero?
Now consider the current trend of going back and re-telling a familiar tale from the villain's POV.
Of course we all know the villain is the hero of his/her own story, but it gives you a different take on them, showing you that they are not the person you might have thought they were.
Apply that to your current WIP. See what changes, what deepens, what tugs at your heart.
You might be surprised.