I have a PhD in maths (applied, though most of my undergraduate was pure), and lectured for a couple of years before moving to a bigger city and deciding to break out of the academic hamster wheel.
My wife already had a job secured, so I had the opportunity to be a little patient. This really paid off.
I considered many of the types of jobs mentioned by others.
Analyst / tech-consultant jobs didn't seem technically interesting enough. Mostly seemed to involved adapting the same framework or analyses to companies' slightly different requirements.
I got through to an on-site interview with an algorithmic trading firm offering huge bucks, but decided I didn't like the idea of moving money around to make very rich people even richer. My dad still says I should try and do something like this for just a few years then change to something more fulfilling.
I was interested in the betting / odds playing type companies and even went to interview with one (rejected). In hindsight I don't think I'd have enjoyed it as much as my current job.
After a month of my CV being online, I was rung personally by the MD of a smallish company that makes software for public / municipal services. He described excitedly the types of optimisation problems he was hoping to solve, and said he'd been looking to hire the right person to work on it for years. The personal touch and his obvious enthusiasm and energy sold it, and I've now worked there for a year. I've learnt and implemented a lot of algorithms and techniques from a broad range of topics - network routing, discrete optimisation, graph theory, markov chains, plus some bonus stuff like cluster analysis and signal processing. It's been more fascinating than all but maybe the first year of my PhD.
I guess my advice is just that these types of jobs are out there. I noticed a couple of other comments about radar tracking and remote sensing, both of which sound awesome. If you have the opportunity, hold off until you find something that strikes you as exciting or even unique. If you don't have the opportunity, perhaps find something "rote" but keep an eye out.