Excellent comments. Here are a few other things:

- Have a separate education section rather than hiding your education inside your work experience.

- Start out with an objectives section. Say specifically what kind of job you're looking for. Do you want a supervisory job? A long-term planning and architecture job? It's okay to say you want to do something beyond what you've done in the past.

- Restructure your "special skills" section. You want to focus on skills that pertain to your objectives. For example, deep in your resume, I saw you mention some security work. That would be an aspect worth pulling out. Maybe you could have a line like: "Security skills: incident response, firewall configuration and planning, ..." When you're talking about your skills, you need to make it more clear what your skills are. When you list "TCP/IP" as a skill, I have no idea if that means you want to work on better policies to eliminate TCP slow-start latency, or if you know how to tell a computer what it's IP address is. Instead, I'd probably have a heading for "Systems administration experience: Unix client and server configuration, Windows NT, 2000, and XP cluster administration, ...", another heading for "Network design and administration" and maybe another heading for "Enterprise system architecture" where you describe big things you've planned and the tools you're comfortable using to do it. You want to show that you're comfortable with low-level details but that you're capable of grasping the big picture of an organization's needs and constraints.

- Simplify your descriptions of each job. I don't really need to know that you installed a DHCP server for a specific job, but rather that you completely designed, budgeted, built out, and maintained all of the network needs to support front and back-office applications for an X-person firm over so many different sites. There's a good chance that somebody reading your resume won't know what DHCP is, but they will be impressed to hear that you took an organization and completely redid their network from the ground up. You already have this, to some extend, in your opening few sentences for each job. I'd extend those opening blurbs and consider cutting the bullets entirely, in favor of an extended "skills" section at the top.

- Do you have any certifications (from Cisco or whomever)? Are you a member of Usenix LISA or any other trade organizations? That sort of thing is important to list.

- Do you speak any languages beyond English? Do you have any other "interesting" skills beyond your job skills? Many people choose to list these things on their resume. It's not entirely superfluous to say, for example, that you're a master woodworker (if you actually were one). That sort of detail might grab somebody's eye and provide fodder for small talk, while they're trying to just gauge whether you'd make for a good cultural fit in the company. (A friend of mine who worked for three months at the South Pole station as a sysadm says that, despite all his experience after that, everybody wants to ask him about the South Pole.)