I spoke with Eric Keeler of LinPC.us today. LinPC.us is the online computer company that is building my new PXLinuxOS computer system.
Eric recommended that I go with an ASUS motherboard. Not only does it have extra USB 2.0 ports, but it also has an external SATA port.
eSATA has extremely fast data transfer rates.
However, eSATA requires it's own power source. this is not a poblem as the eSATA drive is not going to be a mobile drive. I stil have an old 80 gig USB 2.0 drive with its own power source stil conected tomyucurrent compuer.
So, for my purposes, I'll be purchasing a new external hard drive that supports both USB 2.0 and eSATA (like the one on sale at amazon.com above).
I'll move files from my current system using the USB interface and plug it into eSATA on the new system.
Once I have all files transferred to the new system, I'll keep the external eSATA drive plugged in for backup.
And of course, PCLinuxOS fully supports the SATA standard.