Earth day seems like the best possible day to mention a film called Earthlings (buy direct, or watch online for a small fee), which is now also available on audiobook (buy direct). Earthlings documents some of the horrific things that humans do to animals in the name of food, fashion, entertainment, science, and yes, even as companion animals. My interest in animal welfare has increased over the last few years, so the chance to watch this film came at a good time for me. Earthlings was written and directed by Shaun Monson, and for me it is far and away the most heart wrenching, powerful (albeit gory), films of all time. It is extremely difficult to watch -- I had to do so over several sittings, and it was still emotionally very difficult. For me the gory bits were not nearly as horrifying as the cruelty and suffering depicted in this film. I have been in slaughterhouses (part of a veterinary education) and do not mind the sight of blood, but I still found some of the scenes difficult to watch, so those who are sensitive to blood might find the film impossible. If watching the film is too daunting, the audiobook could be a good option. The premise of the film is that we are all earthlings, and that the atrocities committed against animals amount to speciesism and are on par with atrocities humans have committed against each other -- a concept many people may find difficult or offensive. However, the message of the film is still incredibly powerful, and hit home in a way that I have never experienced before. Earthlings is sometimes called the vegan-maker, and you may find that is true for you if you give watching this film a shot. I was vegetarian prior to watching this film a few months ago, but have been considering become vegan since, and today have decided it is time to take the plunge. What better way to celebrate Earth Day?
A full review of Earthlings is available from Doris Lin, About.com Guide to Animal Rights. For a sample of what to expect, you can watch a short trailer (warning, graphic and disturbing images) at the Earthlings site.
For me being concerned about animal welfare does not preclude pet ownership (though perhaps guardianship is a better term). It simply means being a responsible pet owner, and considering all aspects of pet ownership before making the commitment, especially when it comes to exotic pets.

Comments
So glad you’re going vegan for Earth Day! Congrats!! Thanks for reviewing such an incredible film. Hopefully people take your advice.
Beautifully put. Thank you for bringing this to light.