Interesting perspective from respected trainer/strength coach Charles Staley in his article on T-Nation.
Like many trainers, I always follow "conventional wisdom" with my clients, and have them do a comprehensive warm-up, usually with foam rolling, etc. beforehand, before they work out. BUT...when I work out...unless I have something that is feeling particularly gnarly beforehand, I usually just go straight into the workout. If I'm doing something really technical or really heavy, I'll spend some time with specific warm-up of those movements/patterns, but as for a general warm-up, I honestly don't bother. Seems like Mr. Staley is in the same boat.