On a personal front I was in a similar place to you I asked my self the same question, after speaking to several colleagues, should I do R&S or go straight for Security. And in the end it wasnt a difficult choice for me, I went for Security, although I was constantly told it was the more difficult track to take.
I was already a CCSP with a good background in Security, and that was pretty much where my interest lay.
I recalled getting really bored reading through the BSCI book when I started the CCNP, but after starting to use the PIX I found it much more interesting, so switched to the CCSP. In reality I dont think I would have been able to keep up the intense study regime the CCIE requires if I had no interest in the topics.
I'd say if you have good security background and have a real interest in staying in the security field then dont bother with routing and switching go straight for security. Theres not as much overlap as there used to be between the 2 tracks, so its not such a must to have expert level knowledge of R&S, although it definitely helps if you do. There's also a lot less of us CCIE Security folk out there, so all the more inviting .
And after all you could always make R&S your second CCIE
I enjoy security as well, it has always intersted me and I have found in challenging. Having said that, I have been studying alot of CCNP as well due to the fact that it has helped understand how some of the security technologies apply. For example, routing in DMVPN or switching at layer 2. Without some kind of good knowledge of how other technologies work, I find it a little more difficult to become an "expert" in security. I will still do the CCNP/RS track after security though. This is because I deal alot with ASA's, VPN's, etc, in my current job. Seems to be more security orientated than routing (very little BGP, etc).
Whatever you decide, have fun learning it and good luck,
for me, i thing it depend greatly on career you want to built yourself.
right that , to efficiently secure an environement, you need to have strong knowledge on how it have been built, and all concept behind it , this is goal of R/S track.
for my own, study R/S give you a foundation of expert knowledge in general networking. and then you can still go for other track.
but another alternative is that you can go straight to security, but just still reading R/S concept or just use your experience in general networking without passing R/S exam.
I am a CCIE Security and my roadmap is to be a Triple CCIE by next year if possible for me.. Let me give you a little overview to hopefully answer your question.
All Cisco tracks are in itself a field of engineering and architecture and have their own diginity that has stood in the whole world. Also, i would like to add that the foundation of all tracks come from R&S.. eventhough this is true, every CCIE track has its own pre-requisites (not literal most of the times) and you can start any track at anytime this is the beauty. I started my journey from reading on CCENT -> CCNA R&S (but never appeared for the exam for these 2) and started CCNA SEcurity and cleared thsi exam. Now i have reached the stage where i am a CCIE Security written certified and i tell you it is only LOVE and PASSION for thi track that has gotten me here else its not easy here too..
My suggestion, go for CCIE Security then later on touchbase with the R&S track.. you will feel complete.. My Point: YOU DONT NEED ANY R&S TO GO FOR SECURITY THEY ARE 2 DIFFERENT THINGS.
Personal opinions aside, I have know many CCIE Security Candidates who get to the lab and say they wished they would have bushed up on the routing a little more before. All the firewall skills in the world will be of little use if you can't reach asdm from the specified pc in the lab. I have done the r/s track and like one of the other posters mentioned, it was my passion..... now I am finding that I like security as well. I attempted in Nov of 08 and I will say I breezed through the routing.....lol... now i have waited and my written has lapsed but I am on again......
So, I think the r/s is the foundation.....regardless of your current job, having route/switch skillz will never hurt your career. You can't avoid r/s, it will come back to you