It depends on what you are looking to do. You can leave it as DHCP or static. If it is DHCP make sure that it has access to a DHCP server. Keep in mind that access to a DHCP server (or access to any server) will depend on whether you are using an external, internal or private network. Private the DHCP server will have to be another VM on the same host, Internal it can be another VM or the host and external it can be anything internal or external to the host that this machine has access to.
Hyper-V implements three types of virtual networks: external, private and internal. An external virtual network gives virtual machines direct access to a physical network adapters on the physical computer. In effect, the virtual network shares the physical network adapter with the parent operating system (the Windows Server 2008 originally installed on the computer). A private network is used to connect two or more virtual machines running on the same physical computer to one another. An internal network is just like a private network, except it includes the parent operating system as well.