The user login on a Windows 7 / Windows 2008 system is very slow.
There are a number of factors which can affect the Windows login. In some cases, it was possible to speed up the login (against a Samba PDC) by enabling the local policy "Specify maximum waiting time for the network if a user has a user profile saved on the server or a remote root directory" and setting it to "0".
In addition, disabling the detection of slow connections should improve the login speed.
Both settings can be performed using the attached registry file or in the "Group Policy Editor" under "Computer configuration / Administrative templates / User profiles".
Further information on optimising Windows 7 / Windows 2008 in combination with Samba can be found at the following addresses: