Invest in a good Lenses, the body is secondary, unless you need pro-features like ridiculously fast focus. I recommend full-frame, but you'll spend 2-3 times as much money because full-frame lenses are pricey
if you want to just make really good quality video/photos get a
5D mk2, 6D or 5D mk3 with
Cannon 24-105 F4 IS L or Sigma 24-70mm f/2.8 IF EX DG HSM for general purpose
Cannon 50mm f1.4 USM for when it's dark or nice background blur
Samyang 14mm F2.8 manual focus, for the wide end,
Nice to have is also:
Canon 70-200 F4 L IS for tele
100mm F2.8 Marco IS L for closeups
For you to get the best video quality you will need to use the
Magic lantern Firmware (releases the full potential of the camera)
One little fault about the 5Dmark2 is the auto-focus system is ancient: expect to have about 20-30% out of focus photos if you plan to do photography with moving Subjects, (it's absolutely unsuited for sports-photography). The 5D mark3 has a killer auto-focus.
Auto-focus for video isn't usable on any camera that can blur the background, subject tracking is currently too unreliable.
The Blackmagic Pocket Cinema Camera is cheaper than Canon and absolutely destroys it in video quality, but it's very hard to use, requires a lot of know how and it's useless for Photography.
The 5D mk1 can't do video.
Remember Nikon & Sony make nice Cameras too, i just know nothing about those
If you're just looking to make very nice pictures/videos and don't care to dive deep into photography/videography, forget everything i just said and get
Canon 70D with a Canon EF-S 17-55mm f/2.8 IS + Canon EF 70-200mm f/4 L IS USM