From my POV as a hiring manager a CS degree is far less important than a proven history of shipping working code. If you're already in the industry, contributing to open source, etc., you can accomplish a lot more in 18 months out in the field than you could in school.

However, if you have gaps in your CS knowledge, it may be easier to fill them in school. Once you're coding full-time, it can be hard to find the time and motivation to explore as diverse a set of languages, data structures/algorithms, and tools as you are (hopefully) exposed to in a solid CS program.