What is your preferred SLR ecosystem?

Hi All.

I have always been curious why people choose one camera company/ecosystem over another.

I chose Canon because at the time the 50D was the most recently updated camera body in my price-range. Then I bought some nicer lenses and now I am trapped in the Canon ecosystem. I'm not saying that that's a bad thing, but now I can't help but wonder what life would have been like if I went with another brand.

So now it's your turn. What camera ecosystem have you chosen? (Nikon, Canon, Sony, Pentax, various interchangeable lens setups, Leica, Hasselblad)

... and why? (Price, Lens options, specific features, accessories, etc.)

Also, is there anything you hate about the ecosystem/camera/brand you chose?
For Example: The lack of an easy/cheap geotagging solution for Canon (unless I am wrong [which I hope I am]).