I chose Joy readers for my daughter when she's 3. It comes in 70 books for various levels, so the books can cater for her level as she progresses. Hubby and I went down to Edventure to see the various sets and we felt Joy readers have interesting pictures and themes which will stimulate daughter's interest, so we chose this.
I have also bought sunshine and scholastic sight word readers to give her more exposure and stimulate her interest in books. Her kindy uses cambridge readers when she's now 4yo.
We also have some ladybird books handed down to me, so I didnt specifically choose them. But I like to buy books like Strawberry Shortcake, Sesame Street, Barney etc to keep up with her interest. I figure if it's all readers, she may feel "dry", so I buy her fav characters' books to keep her interested.