I just ordered my iPhone 5S, and I didn't have to spend the extra money for the 64 GB model, in part, because I take advantage of Cloud services to manage my music and much of my photography.
Music files, 8 MP photographs, and videos consume lots of internal memory. Now that we have better bandwidth with our cellular, and are often in the presence of WiFi, letting Apple store my music via iTunes Match ($25 a year) and iCloud for photos (free). And there are many great services by others, such as Dropbox, that provide this same capability.
Personally, I like the 32 GB iPhones. They cost $299 with my 2-year AT&T contract (vs $399 for the 64 GB) and provide lots of head room when combined with Cloud services.
The added benefit of using online storage is that all of your content is automatically backed up. When I take a picture with my iPhone, it's immediately copied to Photo Stream. So if I leave my iPhone in a NY taxi, I only lose the device, not those great photos I had just captured in Times Square.