It's best if your HDD is set as primary master. While your CDRW as secondary master and your CDROM as secondary slave. It's important to set the HDD and the CDRW in different IDE so that the bandwidth will not be shared when you are burning CD from your HDD.
<font color=blue>"Some people believe football is a matter of life and death. I'm very disappointed with that attitude. I can assure you it is much, much more important than that" - Bill Shankly</font color=blue>
I would think it would be better to put the CD-ROM drive as the secondary master and the 2nd hard drive as the secondary slave. It'll speed up cd-copying since both the CD Drives aren't on the same channel.