What camera to buy?

To start on this journey I need to get a decent camera. I don't want to spend an arm and a leg on something that is going to be obsolete in a few years. I think of it as an investment and no one wants to have their investment go belly up in a few years.

e're at an interesting moment in camera history because those large DSLR's might not be long for this world. With the move towards mirror-less cameras we are starting to see lighter/smaller devices with incredible range.

o should I invest in a Nikon D800 that might be obsolete in a few years? It's not just the camera I'd be spending money on but it's the many expensive lenses too. Or should I take the plunge on a smaller mirror-less camera like the Sony NEX 7? I'm leaning toward the Sony.