Last year (still get to use that for a few more hours!) when I was trying to figure out what kind of camera to buy I rented a Nikon D600 with a 24-70 f/2.8 lens. Within a few days I took these photos (and more that I'll post later). The quality blew me away and I instantly sold all of my Canon gear to make the big move.
Thought you guys might like to see some of the shots that swayed me:http://www.flickr.com/photos/friedmud/sets/72157639243405373/