Well, from my vantage point (I'm a physicist, in academia), I see increasing demand in several key fields.
(i) Materials science: this is where nanotechnology lives (nanotubes being the obvious very-promising technology here). Lots of exciting stuff here like graphenes, aerogels, superconductive materials and so on. Access includes chemical engineering, condensed matter physics, organic and analytic chemistry.
(ii) Robotics: Very high cool factor, and a technology driven by implacable demographic trends (aging population, workforce replacement, increasing access to hostile environments) and improvements in computing and motor miniaturization. Access includes electrical and mechanical engineering, computer science, mathematical physics, mathematics, and even design fields like industrial design (for those arty nerds!)
(iii) Healthcare: Medicine is a science! Beyond the MD, an aging (and fattening) population demands psychologists (kind of a science... maybe), engineers (interdisciplinary biomechanical engineers are drawn from electrical and mechanical engineering and biophysics), pharmacy (including biochemistry); engineers will also figure prominently in advances in robotic surgery (again, electrical and mechanical).
(iv) Law: like science, but like money too? A PhD in a science plus a law degree creates a patent attorney. I'd recommend biochemistry for the PhD to get on the big pharma gravy train myself, but I can see materials and robotics being big areas in the future. A variation on this would be getting an MBA and getting involved in technology management OR specialized finance such as venture capital focusing on tech/science.
(v) Policy: my first job was as a CIA analyst. While I didn't enjoy government service, a LOT of people live for it, and it can be a very nice, secure career (and a very lucrative background for post-career consulting). A PhD paired with a technology or pubic policy Masters (JFK at Harvard is perfect for this!) can secure a very nice career in the public sector at EPA or wherever (my brother-in-law, a freshly-minted UC Irvine PhD with a Dartmouth post-doc, is now at EPA and doing nicely).
As for academia - I LOVE it, but it's not for everyone. I will say this - it's a bit of a priesthood, and once you leave academia for industry, it's hard to be accepted back again, so bear in mind that can be a one-way trip. Academic science *can* be quite lucrative once you factor *consulting* with industry into the picture (we have at least one Ferrari-driving aeronautical engineer on our faculty, and chemical engineering has no shortage of Porsches in the faculty lot, hehe); a full professor with tenure has absolute job security, two months or more of holiday per year, a six-figure salary, plus income from consulting, books, etc. which can vary from "zero" to "lots"... *that* is a matter of entrepreneurial spirit