The Seagate drives are quiet, I agree. I don't like them because they don't have a power switch so if you want to power it down, you can't. It just sleeps and then wakes up when the OS does a filesystem call, which pauses the OS until it's up and running. The only option really is to either never sleep the drive or unplug it when you aren't using it.
They also take a long time to backup.
I have a Lacie external, which does have a switch but it's not as quiet as the Seagate despite being fanless. It's quite fast though (50-70MB/s).
The Lacie Little Big Disk Quadra looks good and is pretty fast as seen in the chart:http://www.tomshardware.co.uk/charts...mance,694.html
It's 2 x 2.5" drives in RAID-0. If you want speed at the expense of reliability then it could be an option but still, you only get the high performance over eSATA. The FW800 performance was a fair bit lower and it's expensive.
The fastest FW800 (1394b) drive in the chart is the Maxtor OneTouch 3 Turbo but gets poor ratings.
The next one down is the Hitach G-drive:http://www.g-technology.com/products/g-drive.cfm
which is noted in the chart at 74MB/s as well as on their own site. I like the G-drive Mini, which can be bus-powered over FW800. If you get the 7200 RPM version, it should get the 71MB/s listed and because it's 2.5", it should be very quiet. Still, limited to 500GB.