For users on desktop PCs, setting this value to 2 in order for the Num Lock key to be lit before logon is generally a good idea.
For laptop users however, the opposite is true since in most cases the "number pad" is embedded on the actual user's keyboard. Thus, when the user goes to logon to the network, they get an unexpected character from that section of the keyboard. It also gets a little annoying to have to use the Fn key on the laptop every time they logon to turn Num Lock off.
For laptop users, we set this key to "0".
One of our Acer laptops came back from a visit to the warranty depot with this setting enabled for some reason.
From the Microsoft Knowledgebase: How to enable the NUM LOCK key for the logon screen.
Microsoft Small Business Specialists
*All Mac on SBS posts are posted on our in-house iMac via the Safari Web browser.