Stamps gone wild

I feel as the the US post office has sold out and is no longer keeping it real. I first heard about this a few months ago while watching The Daily Show. It seems that you can now customize stamps with your own pictures.
Whatever happened to placing famous faces, artwork, and cartoon characters on stamps? Those were the days. Seriously, I think it would be cool to have a stamp with my likeness made, but I wouldn't actually send a birthday card with my picture in the upper right hand corner with 37 cents slathered across it. That will just give people the wrong idea. My going rate is not that low.
It makes me wonder though. What would happen if you made a dirty picture into a stamp? Would they refuse to deliver? My guess would be that they wouldn't actually make the stamp, so you would have to be subtle in what was being done in the picture(kudos to the post with the most creative idea for how to get around this).
Also, what about the stamp collecting people? I don't collect anything, so I'm not really sure how it works; but my understanding was always that if something is rare, it's worth more. If everyone is sending in pictures of their dogs/cats/children/selves and having only one book of stamps made, rare stamps will become common, thereby making common stamps worth more. The whole economy will collapse, and Canada will probably take over the US. Think about it. I don't trust the post office right now(if I die mysteriously within the next few months it's because someone found out that I cracked the code about Canada's plan to take over the world, I'm willing to take the risk though).