I'm curious as to how many RFCs you have read/partially read or glanced through. Being that practically every technology in IT comprises of an RFC (or several), I think it should be every IT professional's goal to read/partially read at least a few RFCs. Not to learn how a certain technology operates (because the description in the RFC tends to be very lengthy), but to understand why the RFC was written and to get a feel for the layout/format of the document along with the form of language used. I think one thing you'll gain from reading an RFC is that you'll realize that a given technology is a lot more detailed than how it is made made out to be in books/articles.
I can't say that I fully read RFC 1918 and RFC 2730 -- because the writing is very dull and some description is superfluous -- but I'd say that I ready about 75% of each. I also started to read RFC 1771, but decided to postpone that reading until I learned BGP from a different angle. I read parts of RFC 959 when I was having an FTP issue, but shortly after found an alternate solution to my problem.
I hope to look through the RFC(s) that pertain to L2TP, IKE, Kerberos, and SSL. I don't plan on reading them to learn how the protocols operate, because there is text out on the Net that does a better job of describing what I need to know about the protocols, but just to gain insight into the low level details about them.