>Hi all, what account should I run a Windows service under ? It's a filesystemwatcher that will copy any newly created files to a different folder on the same server ( Windows 2008 Server )

I always recommand to use a specific account, one that you would create either on the server or the domain, depending on your needs and how the accounts are managed, so you can apply only the required permissions to what the service does. Then you can evolve the permissions as the service evolves.