For professionals and advanced enthusiasts, there are so many choices at the moment that it is difficult to recommend one camera to everyone. So much of it depends on the intended use of the camera. I have been a Nikon user for over four years now, ever since the launch of the D7000 and have been very happy with my decision to switch. The D800 is my favorite digital camera so far (like my old N80 film camera, but with medium format film-like resolution) and I particularly love the 28mm and 50mm f1.8 AF-S lenses. The D610 should also be a very good camera now that Nikon has worked the bugs out. The D810 will be released soon and offers several small improvements over its predecessor. The DF (pictured above) is a very intriguing, if a bit flawed, camera that has potential to get better with the next version.
Beyond Nikon, the Canon 6D and 5D mkIII are both very nice if a little short on dynamic range compared to the rest of the market. I find myself wishing Nikon made an image stabilized 28mm lens and a smaller 24-70 f4 lens like Canon. Sony, again, has great ideas with the A7 series but has yet to make an acceptable lens lineup to go with it.
Bottom line.. It's a great time for photographers.
Recommendations: Pentax K-500, $420 with kit lens. Nikon D3300, $600 with kit lens. Fujifilm X-E1, $800 with kit lens. Nikon D7100, $1500 with 18-140mm kit lens. Fujifilm X-T1, $1700 with kit lens. Nikon D610, $1800 body only. Nikon D810, $3300 body only.
A lens recommendation: Low price prime 50mm or equivalent for whatever camera you own. I.E. - Nikon makes a 35mm f1.8 for crop cameras and a 50mm f1.8 for full frame, both around $200.