Motivation notwithstanding, I would also suggest that you consider consulting.
I work in management consulting in one of the MBB firms, and we hire quite a few ADCs (Advanced Degree Candidates), particularly in the hard sciences.
The idea is that a PhD provides you with enough critical thinking and quantitative skills that would be extremely valuable in what you do. And you'd be surprised at the type of work that you'd get to do. As long as you have some semblance of social skills that can be cultivated and the ability to think quickly on your feet, you should be fine.
A good way to think about this is what happens when your senior client executive throws some numbers and asks you a question in the elevator -- can you quickly give an answer, and be professional and polite about it without becoming a nervous wreck?
Right now, I work with several PhDs and MDs in the healthcare payer/provider space, and their deep medical expertise is extremely valuable. We have similar profiles of folks with PhDs in mechanical/aeronautical/industrial engineering for industrial goods work, CS/EE PhDs in telecom/media/high-tech industry work and so on. You would be surprised at just how many PhDs, MDs, JDs, and the likes are hired by top tier consulting firms.
Despite what you may have heard of consulting on Slashdot and elsewhere, we do some pretty cool work. Yes, the hours aren't easy and you'll travel a lot, but consider it baptism by fire. In a span of two years, you would have worked on a wide array of projects and will have honed your hard and soft skills -- everything from building financial models to presenting to very senior executives.
And surprisingly, you will work with some very smart people. Yes, many of them may have MBAs, but just as many have other advanced degrees, and even the ones with MBAs also have pretty strong undergrad credentials (e.g., Harvard, MIT, Stanford), usually STEM.
So, whatever your motivations may have been, I will just say that consulting will teach you skills that are very hard to acquire elsewhere. It may be baptism by fire, but your value in the job market will grow by leaps and bounds.
Something to consider. :)