DNS namespace considerations in Win2K

I am in the process of upgrading our corporate domain from NT 4.0 to Windows 2000. My question is regarding choosing the domain name/DNS namespace during the Win2K migration. We are currently on the internet with a registered domain name, .org. What would be the considerations in choosing the internal namespace for our domain? What are the pros and cons of having it the same as our external (registered) namespace? Thanks in advance for your help.

Kelvin Tamayo
Network Administrator
MCSE NT 4.0 and Win2K