I have been tasked with migrating a system I inherited off Windows server 2k3 with exchange on it. This is a DC with exchange 2K3 installed (not by me). I want to migrate to Server 2008 and Exchange 2010. I will be installing Exchange 2010 on another server and have a single DC running 2008. My question is which should I do first? Install Server 2008 and Exchange 2010 and run in parallel with the 2k3 box and then migrate the DC to Server 2008? Remember the current DC is running Exchange as well as AD, DHCP and DNS.