I need to get a new phone.

I was thinking that I should just get another 5 (that's what I have now) as it would be cheaper. But I also have a 16GB now and I would prefer to increase because my phone gets full so fast. AT&T only has the 16 and 64 for the 5. So, it would be between $300 for a 5 @ 64 or the same price for a 5S @ 32 (or $100 more for 64).

If I am already spending that much money I just assume choose between the better model as the cost savings diminish somewhat. But I don't really know if a 5S is necessary.

Help.