properly managed security should be transparent until the user runs into a blocked site/etc
I agree and would argue that where I presently work, the system is anything but properly managed. Mostly this stems from blanket directives and policies issued by corporate headquarters. I am also well aware of the nothing less than heroic efforts on the part of our local IT support who bear the brunt of much of this.
At the same time, I think what gets lost in the one size fits all "security" policy is that there are different groups and classes of users. For example, I am in new product development and colelctively we represent a very small percentage of the support base. As part of our job, though, we are required to use heavy duty applications and work with hardware that is networkable (including our own products) on a very low level. These applications are typically not compatible with all the "junk" applications that are installed to keep us from bringing mal-ware into the works. We are also typically much more knowledgeable and "security" concencious than the typical office or factory work. I don't want to make any statements that will curse myself, but I think it is obvious what I mean by this.
What seems to happen though, is that attempts to shoe horn our work, tools, and equipment under a generalized "security" policy is that it greatly impedes our ability to do our job. For example, if you make it impossible for us to maintain a version control system with our contract engineering firm you bring software development to a grinding halt. Since this can't be tollerated and attempts to get these issued resolved through appropriate channels are met with extreme resistance, ways around it are usually found.
As I mentioned, though, we are a small group with knowledge, skills, and responsibilities that are far in excess of the typical user whose responsibility is to push paper through a database application. We also tend to be quite security focused ourselves as it is part of our job and often times part of our personal hobbies being computer oriented individuals.