AND THE WINNER IS....
... the Seagate Barracuda 7200.11 One Terabyte 3G SATA drive (ST31000340AS). It out-performed the other three 1TB drives in 7 out of 8 tests. It's pretty amazing to see a 7200rpm drive transfer at over 100 megabytes per second. Eat your heart out, Raptor 10Ks!
The Seagate 7200.11 is available in smaller capacities (500GB and 750GB) which feature transfer rates equal to those published here.
We were puzzled by the Hitachi Deskstar 7K1000's poor performance in the Disktester sequential READ test. We can give you two factoids on this issue:
1) We tested all drives internally to the Mac Pro 8-core. When we tested the Hitachi externally using the LaCie 3G SATA host adaper, the read speed average jumped from 57MB/s to 81MB/s.
2) The Ultrastar version of the 1TB Hitachi was tested by AMUG and performed much better in the Disktester large block test.
The Western Digital 1TB Caviar GP's claim to fame is that it is "green." It's supposed to use less power and cost less than the others. We saw them selling for as low as $279. That's $50 cheaper than the Seagate 1TB drive.
The Western Digital Caviar SE 16 (750GB) was nipping at the Seagate 1TB's heels. Selling for as low as $189, I would give it the "best bang for the buck" award if you are looking for a large capacity boot drive.