It really is personal choice. I've had inside, outside, and outside balcony. For me, it just isn't worth extra money because I'm not in the room that much. I'd rather be out and about. One of the best quotes I recall on this site in regard to this goes something like this "Consider a hotel analogy. Would you rather have a hotel room with or without a window"
Now on some cruises I think it may be worth it. Any cruise that spends a lot of time cruising exotic scenary, e.g. Alaska, Chilean Fjords....but for me I'd rather be in the public areas than on a balcony. I'm more extraverted than introverted.