I would recommend that you go further than that. Update your resume at least quarterly. Have friends who are super-freakin'-nitpicky and ask them to go over your resume with a fine-toothed comb. Return calls from recruiters.

My specialty is in high demand, and occasionally I will take an interview even if I'm happy where I'm working. This tests not just the interview suit but the interviewing skills and procedures. It also helps you understand better what the market for your skills are like. Don't lead anyone down the garden path -- be clear about your level of interest. You know your industry better than I do (unless, perhaps, you're in network security) so don't do this if it will burn any bridges. The idea is to use this time to build your bridge-building skills.

For me, LinkedIn has been highly valuable. InfraGard has been valuable. (ISC)2 can be a tremendous time sink -- but the cert I earned had a huge and lasting impact upon my career. I like the idea of ISACA and ISSA but don't have a lot of time for them. Most important to me are the industry contacts I make and maintain. It's very handy to have a good reputation.