I was never a huge Mozilla fan until now.... Now I am in the tank, at least for the time-being. 2 things put me there: the very excellent new "Nightly" x64 browser that is on par with the best of any browser experience, and even more so the intro of the "Collusion" add-on. If you haven't tried it, I urge you to do so asap.
I'm attaching a screenshot of my Collusion profile after a mere two hours of light use this morning. A simple mouse-over of any subset of the diagram reveals the tentacles of privacy-invaders hooking your system, and displays data, if its known, on the Tracking firm in the upper left corner.
With the raw data that this arms users with, I hope it will be a short time before some clever programmers come up with a way to aggressively resist the worst offenders out there by counterstrike measures, collaboratively. There are a lot of us, and not so many of them by comparison.
Watch this 7 minute well-executed presentation by Gary Kovacs, it is very informative. Gary Kovacs: Tracking the trackers | Video on TED.com