I agree that it's perhaps not the best idea for cancer genome sequencing, but current 2nd-generation sequencing should be beneficial for the standard human genome. Even at a cost of $10,000 per person, you may be able to substitute a single expensive drug for a substantially cheaper generic when knowing that a person has (or doesn't have) a particular mutation. As long as the sequencing is high enough quality (as you should get from a long paired-end Illumina run), it only needs to be done once, and then can be re-used for whatever new genetic discoveries come your way.
I've wondered for a couple of years now why drug companies aren't already doing this (or at least subsidising the cost of sequencing). Some drugs have been brought back from the brink of rejection via genetic tests, and given the high cost of drug research it makes sense to do a relatively cheap genome sequencing if it hasn't been done on a person previously. The cost of whole-genome (and whole-transcriptome) sequencing is now in the range where research institutes are starting to consider it as a routine operation, and it won't be long before it falls into the price range of a cost-conscious consumer.