To be able to personally tailor medicine to an individual, you need an effective diagnostic mechanism, and an effective way to decide, based on the diagnosis and the patient, what course of treatment will work. Trying to do this on the basis of a patient's genetics is unlikely to be effective in the near future, if at all.
Te begin with, studies of the kind we see today tend to give results like 'gene X affects incidence of disease Y by n%'. To rely on this for a diagnosis and treatment amounts to a guessing game, and the number of such n% guesses compounded together will cause accuracy of the diagnosis to be little better than random chance, yet appear to have the certain blessing of the medical establishment. Establishing the effect of a gene is, in any case, far less certain than seems to be made out, because there is little understanding of how an altered gene causes a problem even if a correlation is detected.
I fear personalised medicine is the road to mass Russian Roulette medicine, and I hope the 'brave new and shiny' factor doesn't cause it to be overly relied upon.