Finally got my dead RAID card replaced. Have set up 3 of the Hitachi drives in a RAID5, and no problems so far. Array is just initializing at the moment, but it formatted ok in Windows, which is further than i've been getting with the Samsung drives running in SATA II mode.
Once completed...
Ok, thanks.
I might look at FlexRAID as well, but still looks very much in development.
I've got backups, but its a hassle having to "maintain" RAID arrays every couple of weeks.