I am using the my MC-30 on both my D3 and D700. It works perfectly because both cameras have Nikon's standard 10-pin port. I own an MC-36 but never use it. I tried it on the D700 a couple days ago and again, because it uses the standard Nikon 10-pin connection, it works perfectly on the D700.
The MC-36 is far too expensive for simple remote shutter release use. Unless you needs its built-in timer control features, stay with the MC-30 which has a remote trigger button as well as a sliding lock switch for Bulb exposures that you time yourself.
The Modulite ML-3 is only a bit more expensive than the MC-36 and has the advantage of being infrared (untethered). Just keep in mind that you have to have line of sight between handheld remote controls and sensor on the Modulite receiver mounted in the hot shoe in order to trigger the shutter. Also note that if you're using the hot shoe for something else (like a flash for instance), you can't use the Modulite.