From Gawker (oh yeah, I admit it), people are wearing flip-flops to work. Flip-flops are abundant at Microsoft. Flip-flops are incredibly abundant in my closet. I can imagine situations at work when they aren't particularly appropriate (and I do pick my outfit relative to who I am going to be seeing that day). At the same time, my cute little navy canvas ones with lobsters on the straps are just begging to be admired.
I'm not sure I know the right answer, and I suspect it's mostly contingent upon the accepted dress at work. And I'd never wear the super rubbery thrift store kind to work. And flip-flops make foot grooming a requirement.
If I say it's OK to wear flip-flops to work under certain circumstances, does it mean I have lived in Seattle too long? I mean dress flip-flops, definitely dress flip-flops.