I agree that eSata is the way to go, but you are seriously wrong in your calculations. I have a 500GB version of this hard drive and it did take a while to backup all my MP3's to fill it up -- in 3 - 3.5 hours.
The problem with this drive is that it is not the Pro version so it "probably" has a 2MB cache as does the other Freestyle drives (I say probably because even the Seagate.com site does not answer this question).
If you are going to be using it as a backup device, go for it, you will be fine, if it is going to be an active drive, skip it and get something like the
Cavalry 1TB drive with the dual eSata & USB 2.0 interface. I have 6 of these in my lab at work connected to different machines, plus 2 at home. Nice thing is you can move it to a computer that does not have an eSata port (like a laptop) and still utilize the speed benefits.
Just my 2cents.