Currently Sony A7s with Atomos Shogun for 4K, Phantom4 for aerial and Canon 5D Mark III for photos (i used it for HD video in the past).

I use a Canon 5d Mark II since 2011, but today I'm considering the Canon 100 with Atomos Ninja 2. 4K would be ideal, but since I shot other kinds of jobs and need a run and gun option, the C100 seems a reasonable option with all the discounts.

I'm not a tech but investing quite heavily in a non-4K camera nowdays seems a bit strange to me. I regret such a great amount of my stock content was shot in HD...

I started with an Canon t2i (550d) and some of those clips still sell. My Gopro hero 3+ black gets quite a bit of usage as well even today. I then moved up to Samsung NX1 and the results were amazing. Its a shame that Samsung has stopped supporting the NX1 
However all output 8 bit codecs (h.264, h.264 and h.265 respectively). With these cameras outputting 8 bit delivery codecs - color correction and effects work (green screen in particular) suffers from macro blocking, banding and other artefacts - I've had enough and upped my game in a big way.
I recieved a Blackmagic Ursa Mini 4.6k last week and am still stress testing it and have to admit that it is in a totally different league. 12bit RAW 4.4.4 chroma subsampling, Prores XQ, 15 stops of dynamic range (as advertised) its a different beast altogether. Its a bit overkill purely for stock though...

Let me also be the first to say that its not so much the tools that matter but what you do with them that counts. Content is always king, and an iPhone in the right hands will produce better results than an Arri Alexa in the wrong hands.