I've become fond of saying that GTD is not a motivational system. Once I got over the novelty of having complete, updated lists of the things I should be doing, I saw that they weren't actually getting done.
I did (and do) get great organizational benefit from GTD, and I have stuck with it much longer than any other organizational/productivity system I have ever tried. But GTD brought my procrastination into sharp focus.
For the past 6-8 months, I've been fighting procrastination much more than I've been fighting disorganization. GTD works well for me, and now I've moved on to the next roadblock on my path to stress-free productivity.
If it weren't for GTD, and the models of useful GTD discussions I have found online, I never would have started my procrastination group -- see link in my signature.