It's actually quite exciting creating a nursery for a first time parent. Like all rooms a nursery must work for you and your new arrival. Personally I don't like nursery's to have a 'theme' I like them to grow organically with the child. However having said that the nursery will reflect the parents taste and preferences.
On a practical side everything needs to be easily stored and cleaned.
Here are a some examples of Nursery's and toddlers rooms, as you can see very different styles.
As you can see each room is practical but with a unique style.