If you are currently using DHCP, changing your IP addresses won't be that bad. First, plan out the static IP addresses for your domain controllers, DHCP servers, DNS servers, and any other server. Move your network equipment over first, reconfigure it, and make sure it's all working. Then, move over your DHCP servers, and reconfigure them for the new network. Be sure they're handing out new IP addresses for the gateways and name servers. Move over your DNS servers and change the static DNS addresses you have -- don't worry about computers that use dynamic DNS. Then, move over your domain controllers and other servers. Finally, move over your client computers.
If you're not currently using DHCP, this would be an excellent time to switch to it. You're going to have to reconfigure all your client computers, anyway, and DHCP will make it much easier as your users start using more laptop computers and networked PDAs.
The domain profiles should be fine -- they're not dependant on IP addresses or names, but rather a unique Security ID (SID) that will stay with the computer through the move.
This was first published in October 2004