From a software standpoint there isn't much of a difference.
· Enterprise limits you to something like 4 virtual machines whereas Datacenter has no restrictions.
From a hardware standpoint there are some big differences.
· Datacenter will let you add/remove/swap processors and memory while the server is running. Enterprise would blow up.
· Enterprise supports up to 8 x64 sockets, Datacenter supports 64 x64!
Still using Enterprise should be fine.