I could consider myself to be a digital native only because I grew up with computers and video games. However, I think an important distinction needs to be made between my digital native-ness, and young people today who have grown up only knowing a networked and connected world. I therefore suggest a third category of "Digital Naturalized Citizens" who are not necessarily natives yet have assimilated very well into the "Digital Native" culture. I feel that I most appropriately fit into this category.
I notice digital natives in the schools where I have worked, these students instinctively texting or IM-ing a friend before calling that friend on the phone. I have also noticed countless digital natives, mostly in the form of instructors, who believe that learning takes place through delivery and acquisition of content knowledge, rather than through construction of understanding through meaningful and authentic tasks.
Prensky's contrast of "Legacy" against "Future" content is interesting, but I feel that identifying discrete disciplines perpetuates an old model of education where instructors tend to only have one area of domain expertise.