Chem PhDs are highly desirable patent attorneys, especially in the pharmaceutical areas. It's hard to find people who have gone through so much schooling.
I would never recommend going to law school unless you really want to be a lawyer. It's just too much time, torture and money otherwise.
I would recommend, however, that you consider being a patent examiner as a backup career. The patent office has been
hiring aggressively for the past few years to try and address the huge backlog of patents waiting to be examined (the 2012 budget includes
1,500 new examiner hires). An advanced degree is not required but would, of course, help you obtain one of these positions. It's my understanding that it's not difficult to get a job as an examiner due to the demand. The best thing of all is that to get hired as a patent examiner, you do not need any prior experience or knowledge of patents! The USPTO hires people with scientific backgrounds of all types and expects to train them fully. The PTO is also really great in that it has incredibly flexible hours for examiners and the office is essentially virtual so, after training, you can work from anywhere in the country. An advanced degree + a few years at the patent office would also make you a great candidate to be a patent agent after leaving the PTO (see above for description of this career). I suppose it's also possible to transition from a patent examiner role to a science role as well if you just need a job for a few years while the economy is in the crapper.