<p>I'd suggest the d750 for it's better low-light autofocus (compared to d600/610) and for it's smaller size/weight (compared to d800/810.) Having said that, if the cost of the d750 inhibits you from buying the proper lenses for your needs, then the d600/d610 are perfectly fine for almost everything. I have the d600 and love it- it occasionally hunts a bit in very low light, but the files are great. I shoot it a lot with the 28 and 50 1.8 lenses. </p>