gary, sATA drives connected via sATA is a very good solution - i'd say no need to experiment with software raid.
NCQ is Native Command Queuing (aka Tagged Command Queuing) - a technology originating from SCSI.
in a nutshell: if the operating system (OS) requests data (say portion A-B-C-D, 512 bytes each) which resides in different sectors of the harddrive NCQ can re-order the requests (say to B-D-A-C) to minimize the movement of the heads (in the harddrive) - this reduces seektime to the half (average 8,5 ms to 4,5). this happens in the interface sitting on the harddrive itself.
a hardware raid makes only sense, if you can be sure it does not try to cache files (and so effectively reducing your performance) and also uses NCQ _and_ an intelligent read-algorithm.
my example here:
IBM expansion unit SCSI 160 drives, i5 controller, raid5 = ~20 MB/s
EONstore (sATA drives to SCSI), 39160 controller, raid 5 = ~120 MB/s
your sATA drives should give you around 60 MB/s and i'd assume you will not reach this limit with any arrangement, especially if the (instumental) sections are spread across several drives. sATA I (the bus itself) is 150 MB/s - capital B means Bytes
christian
christian