A few weeks ago, I asked a question out around what other certifications people took and which ones they found the most valuable. A somewhat related question is what other professional organizations or groups people are involved with in addition to (ISC)2 and what they find valuable about those associations that others might as well.
Expanding the sources of domain knowledge, as well as the ability for security professionals to influence those domains for the better is valuable in itself.
Since I'm asking, I'll start first:
I also recently joined the Austin (ISC)2 chapter and attended last month's event. I'm planning on attending February's also. Previously, in the Baltimore area, I occasionally attended CharmSec which is a "CitySec"-style meetup group of a security professionals, as well as CharmBUG (BSD User's Group), the members of which also had a big security focus (which is no surprise, given the area).
I've been involved in OWASP in the past, but haven't been for a while. I'm thinking about revisiting that though.
There's no ISC2 chapter in New Orleans (AHEM!), but I am a member of the local ISACA group, which has events fairly regularly. There's also a home-grown entity called NOLASec, which is absolutely phenomenal; they host a BSides conference each year which is every bit as good as the big, international get-togethers, and they also do monthly meetings at a local bar which are very well-attended.
I am a member of the local ISC2 Chapter, on the Board of Directors of the local ISSA chapter and also serve as a Board member for the local InfraGard chapter.
Once a month a small informal gathering of local IT security leaders across industries get together to discuss hot topics and areas of interest.