Any philosophical novels similar to 'Sophie's World'

So I'm nearing the end of 'Sophie's World' (A fantastic book), which is a novel containing a lot of philosophy in it.

The philosophy in the book... (nearly) completely changed my view of the world, and now I want to read more books similar to it :D - I'm craving philosophy XL

So can anyone suggest a book which is similar to 'Sophie's World' ? :3

I recommend you read the works of Haruki Murakami, they can be very philosophical. The man is a genius.