I have ordered 23andMe personal genome kits for the whole family. The price is right and the technology seems to be mature for the near future. Honestly, as much as anything, the reason for doing so is not to learn anything new about my ancestry as it is to confirm my confidence in the testing system.
I know a great deal more about my ancestry than most people. I've met numerous third and fourth cousins, have met relatives from Finland (whom my parents and brother visited in person), and I am familiar with the time and exact place from which my German ancestors emigrated (my father was finally able to meet some of my relatives there when West Germany and East Germany merged), and I have a fair amount of familiarity with my Irish ancestors (although no one in my family has made contact with my Irish relations).
We also know quite a bit about my wife's Korean ancestors and could probably trace their ancestry for hundreds of years with a visit to Korea if I spoke Korean and the relevant records weren't destroyed or placed beyond reach in North Korea during the Korean War.
We've been close enough to family that we also have a reasonably complete medical history, and genetics is still enough in its infancy that even if 23andMe were allowed to make medical commentary of the raw genome data (for the foreseeable future it is prohibited by the FDA from doing that), the predictions from our medical history would probably be more accurate.
We also know at least some of our relatives are in the system and might pop up as related. And, of course, we have actual phenotype knowledge about ourselves that can be matched against those genes for which phenotype-genotype relationships have been established (e.g. eye and hair and skin pigmentation, ear wax type, etc.).
Still, it will be fun to see the results, and to see the strong predictions that I can make about them fulfilled (or contradicted) in detail.