Moving SBS 2008/Exchange to a new box

We have SBS 2008 server with Exchange. I am planning to rebuild the entire network for this company.
I am setting up the following:
?Windows 2008 server with AD, DNS, DHCP, GC, etc.
?Windows 2008 server 64 bit for a new Exchange enterprise.

I want to move the old exchange from the old SBS 2008 to the new exchange without loosing anything.

What is the best way and procedure to do this?
Help and discussion would be greatly appreciated.