Chuvakin has a great post over at his blog where he talks about what skills you should be focusing on, such as skills that help land you jobs or skills that help you do jobs. I think I agree with all the points made.
Getting past an HR filter to land a job is a sort of small-time thing. You can apply for 20 jobs and you just need to get through and hired once. After that, you have, usually, several years to either prove your worth or get booted out for not being able to do the work. The bottomline is you need to be able to do the work.
I also believe that the deeper and more versed one becomes with the “skills that help you do your job” the easier it is to demonstrate those skills to someone else. For instance, it might seem hard to demonstrate a web app weakness to a manager…unless you’ve done it so much you can pretty much spot them on sight (insert some allusion to MagicEye pictures that often take a lot of work to see the first time, but once you get it, you can get it faster and faster).
You know you’re good with a router or firewall or load balancer when someone throws you a strange question and you figure out some interesting way to do it that wouldn’t have been obvious without a few years of experience. That skill might not get you a new job, but it will certainly cement your place in a current job!