You definetly want to do the update, below are all the changes that 2.00 and 2.01 grant you (I have no clue what 1.0.1 fixed over 1.0).
From the above referenced Nikon site 2.0.1 gives you the following fix over 2.0: An issue that, in some rare situations, caused the battery indicator to blink with shooting, regardless of actual battery charge status, has been resolved.
Performance of the 5-area AF system has been improved (Dynamic area and Closest subject AF-area modes).
Changes have been made to the design of menu displays.
Page-size settings can now be applied from the camera with direct printing from a PictBridge-compatible printer.
The number of exposures remaining, displayed in the control panel and viewfinder, when shooting at an image-quality setting of NEF (RAW) or NEF+JPEG Basic has been changed (the number is calculated based on the size of compressed RAW file). Maximum number of exposures displayed when a 256-MB CompactFlash memory card is used:
Version 2.00: NEF (RAW): approx. 44 exposures; NEF+JPEG Basic: approx. 39 exposures Version 1.03 or earlier: NEF (RAW): approx. 23 exposures; NEF+JPEG Basic: approx. 21 exposures
The default setting for camera clock has been changed from 2004.01.01 to 2005.01.01. Now you cannot set the clock back to a date before 2004.12.31.
A problem that sometimes caused communication between the camera and computer to be unexpectedly terminated when using Nikon Capture Camera Control has been corrected. (Windows)