16GB or 32GB iPhone 5?

I am currently living in Australia, and am in the process of getting an iPhone 5. However, I am torn up as to which storage size I want for my future iPhone.

For me to have the 32GB model, I will need toay an extra $4 a month, which comes to an extra $96 over the life of the two year contract.

I have previously owned a 32GB iPod Touch, and found that especially with the increased use of my iPad, I don't need anywhere near that amount of storage on that device.

I'm not sure whether to play it safe and shell out the extra $4 a month for the 32GB, or whether 16GB will be enough, saving me $100