Currently for 3,5" drives there will be only two companies:
Seagate=Maxtor, Samsung, Quantum
Toshiba=Western Digital, Hitachi, Fujitsu, IBM
I think they were sticking with WD last time, so they will go for Toshiba drives.
Mac Pro 2006 - Seagate 250 GB
Mac Pro 2007 - Seagate 250 GB
Mac Pro 2008 - Seagate 320 GB
Mac Pro 2009 - Western Digital 640 GB
Mac Pro 2010 - Western Digital 1 TB
Seagate=Maxtor, Samsung, Quantum
Toshiba=Western Digital, Hitachi, Fujitsu, IBM
I think they were sticking with WD last time, so they will go for Toshiba drives.
Mac Pro 2006 - Seagate 250 GB
Mac Pro 2007 - Seagate 250 GB
Mac Pro 2008 - Seagate 320 GB
Mac Pro 2009 - Western Digital 640 GB
Mac Pro 2010 - Western Digital 1 TB