Ditto. For me, the 20 minute investment in a post-lunch nap pays back manyfold in increased productivity (to say nothing of health and general well-being) for the rest of the day.

Finding a place to nap in an office an environment can be tricky, but if you start thinking of your nap as an important work tool and not an embarrassing indulgence, you can usually find a way to make it work. Drop a few bucks on a good pillow, blanket, sleep mask, and/or white-noise headphones -- whatever's important for you -- to keep at your desk. (For me, the sleep mask is critical. YMMV.) Get creative with your sleep position -- couches are great, but I've made it work lying on the floor with my feet up on my office chair (suitably chocked so it won't roll away). The key point is, don't be afraid to ask the work environment to adapt to your nap, rather than vice versa.