I'm starting to think about my next photography purchase and it's looking like a decision between two items. I currently own a Nikon D700 with the following lenses: 50mm f/1.8, 20mm f/1.8, and 70-200mm f/4. The two items I'm considering purchasing are either a Nikon D750 or a Nikon 24-70mm f/2.8. The D700 performs well for me, but I understand that it is a bit dated (however, mine is only lightly used as I received it from someone who barely used it). I would love the enhancements of the D750. On the other hand, my lens lineup could use an addition in mid-range. The 24-70mm would help a lot here. The D750 is now $2000 and the 24-70mm is roughly the same. I would appreciate any advice. For reference, here's some of my work: https://500px.com/mqnielsen.