I'm no CCIE, but I can agree with timmedin... I can tell you if you focus on security, and don't really buckle down, based on what I've heard of the CCIE exams, you WON'T get through them in one piece. If your heart's set on CCIE, then I'd focus on the networking side. If you TRULY like security (and more than just Cisco security) then I'd definitely lean towards the CISA and other security-related study.
It's very difficult, at least for me, to even consider finding time, these days, to try to focus on multiple disciplines. While no CCIE, I thankfully was brought up in the networking world first, and have a good grasp on it. It does help with security, to have the background. Does it require CCIE or similar expertise...? No.
If you have questions with regard to time required to study for said certifications and training, or what materials and experiences you might want to gain for an individual topic, there are many people here to help guide you. However, we can only guide you in decisions based on your goals, and if you don't have those figured out, clearly, yet, then that's all we can do, is to support you and give you knowledge towards you making your own decision(s).
So look at what you REALLY want to do, factor in your current employment / study status, and make a clear decision about what YOU want to do. If that means a career change to accommodate, or a shift in philosopies, scheduling, etc, than those are areas you'll have to weigh in for your decision. Unfortunately, we'd all be in the wrong, if we told you to go one way or the other, as your heartfelt feelings and goals are not something we can truly know. All we can tell you is the paths we've chosen, whether or not we're happy in our paths, and how those paths have benefitted us / our jobs / etc. In my case, I stayed security, and I LOVE it!
~ hayabusa ~
"All men can see these tactics whereby I conquer, but what none can see is the strategy out of which victory is evolved." - Sun Tzu, 'The Art of War'
OSCE, OSCP , GPEN, C|EH