MS Office 2007 crap
To work around a fscking annoying behaviour of MS Office 2007 regarding files on network shares you might want to use something like the following inside your smb.conf:
create mask = 0660 force create mode = 0660 directory mask = 0770 directory security mask = 0777 security mask = 0660 force security mode = 0660
And to fix another annoying problem (reconfiguration of Word 2007 again and again) use:
Windows Registry Editor Version 5.00 [HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Word\Options] "NoRereg"=dword:00000001