Can we get past the "I don't need it so nobody does" responses? The most helpful responses relate to how the purchaser intends to use it. If he's going to be within 3G or WiFi range most of the time then it's obviously not going to matter as much as if he's traveling outside of Internet range. I've been on several trips with my iPad where I spent days away from Internet contact and even when I had it it was so expensive that streaming was not an option. So added storage was a boon.
Because the people that respond with that are most similar to the majority of the population. A fellow poster can agreed with his idea and know that 16GB is the right fit.
32GB is too much space and 64GB you are just throwing your money way.
Stick with 16GB