Transferring 3 Databases From Both Express 2005 And Standard To New Physical Server

I am trying to figure out the best method for transferring SQL 2005 databases from 2 different physical servers to a new server running windows server 2008 64bit.I own a fully registered copy of Microsoft SQL 2005 32bit Standard Edition. However all of my SQL databases together are only 4GB in size thereby making 2008 SQL Express an option.

Here is the breakdown of the servers:

1) (Old Server1) Windows 2003 Server 32bit - SQL Express 2005 32bit
2) (Old Server2) Windows 2003 Server 32bit - SQL Server 2005 32bit Standard
3) (New Server) Windows 2008 Server 64bit - (Not sure which version to install)

**The objective is to migrate 2 SQL databases from Old Server1 and 1 SQL database from Old Server 2 to the New Server. What version should I install on the new server??? Do I go with 2008 express or install the 2005 Standard Edition?

Pending your response to which version to install, what are the correct steps to migrate (which I have never done before) the databases from both of these servers to the new server? I think this particular situation is unique in that I am transferring from both SQL Express and Standard from 2 different physical servers to a 2008 server that is 64bit.