I guess most of you might already know this, but until today I didn't know that on the prosumer D700 & D800, one can lock the shutter speed (e.g., at 1/200), via custom settings. Previously I thought this feature was only present on the flagship Dx cameras (i.e., the special "L" button on the D3 series).
A few times while using strobes I've inadvertently "bumped" the shutter speed past the flash sync speed resulting in the familiar black bars, when all this time I could have just locked down the shutter speed. :O
This setting is perfect for the studio. I.e., with the camera on M, the shutter speed can be locked to the sync speed, then the aperture can be changed to taste.
The shutter speed lock is custom setting f8 on the D700 and f7 on the D800. One can also lock the aperture from the same menu. On the D800, the fn button can be assigned to enable/disable the locks.
This feature doesn't seem to be present on consumer-oriented models (e.g., D7100, D610).