Having interviewed quite a few people, I tend to think that there's a correlation between not just a degree, but also the quality of the school where it was attained, and the quality of the candidate - as measured by his/her professional knowledge and ability. That's not always true. In fact, of the two best coders I know, one didn't bother with a degree, and the other did it as an off hand, graduating after 8 years, having worked full time all along. Nevertheless, when it comes to people I don't know, and given that I don't have the time to interview everyone who sends their resume, a degree serves as an initial filter. If the resume is impressive enough without it, then I'll go ahead and interview, but it has to be really impressive. In short, not having a degree is an impediment. You can succeed without it, but you're putting yourself at a disadvantage.