? Upgrades? DSLR-Body 1DMk4 vs 5DMk3 vs 1Dx?(Category:EOS Digital SLR Bodies)

To all Forum readers/contributors and Photographers here!

Please could anyone have some good advice to me!
I do have some serious plans to do one upgrade of my set of DSLR-Bodies!

But I feel quite unsure to make the very best and balanced decision if maybe choose the older (there are some mint-condition for sale now) of the 1DMk4 or go all for the new version of 5DMk3 or maybe going all the way to the newest 1Dx?

Main subjects are:

* Macro (flowers in nature)
* Landscape/skyscape
* Birds also BIF and animals
* Low-light-conditions in the nature with flowers, birds, landscapes

(I already have some good primes and they are mainly only the so called Canon "L"-lenses which I use together with my 7D and 5DMk2.)

But I do also have additional plan to purchase either the new version of EF 500mm f/4L IS USM II or maybe rather (when using full frame) the Canon EF 600mm f/4L IS USM II also wish to upgrade my EF 300mm f/2.8L IS USM Version I to the version II because of the better MFD and 4-step IS and two flourite-elements making it very good with my Extenders EF 1.4x III /2x III.

I prefer hand held wildlife photography and walking around in every kind of environment in the nature and I still do not even have a monopod but yes I do have sturdy tripods (Gitzo systematic 6xCarbon) but no Gimbal head yet for the tele lenses.

That is me in a nutshell right now.

Thanks for spontaneous thoughts and if you have time and opportunity for your valued advice!

Best Wishes!