Client connection tool for 64 bit SQL 2008 server on 64 bit Windows

We have Access 2003 and Access 2007. They are currently using the SQL driver from the Access (Mdac) to connect to SQL 2005. Sincewe will be on the SQL server 2008 64 bit version, What is the correct SQL network connection client they should be using? Should I use their existing drive for SQL 2005 or I should install the native 32 bit client connection tool from SQL 2008 installation CD? I want our Access application get the best performance from the SQL 2008 64 bit platform? Any pointers is very much appreciated.
wingman