take visiting professorship or wait a year? I've been doing a post-doc in physics for the past 5.5 years or so and have unsuccessfully tried to obtain a faculty job at a University for the past 3 of them. On a whim I applied to a visiting prof. job at a nearby (pretty highly regarded) liberal arts school and got an offer. It's for a year with maybe extensions. 

I am wondering if I should take it and if I do, do I shoot myself in the foot when applying for University positions in the fall? How will they look at it? The job entails one class and 2 labs/semester so I'm somewhat hopeful that I can continue a reasonably good research output in the year.

On the other hand, this experience will give me, hopefully, the necessary requesites to break into the lib. arts academic setting which I'm not to adverse to either.
This is ultimately a personal choice, but if you've spent the last five years as a research postdoc with no success in landing a tenure track position at a research university, then it's probably time to change your career strategy.  

There are lots of permanent or tenure track positions at liberal arts colleges, regional comprehensive universities, and community colleges where little or no research will be expected of you and PhD and teaching experience are necessary to get a job.  If you want one of those jobs, then now would be a good time to start getting more teaching experience.