well, another vote for SCSI and the warpengine controller. The WarpEngine SCSI controller seems quite fast to me, perhaps twice as fast as the DCE 1230 SCSI module on my A1200T, using the same 2.1GB HDD, and 100MB Zip drives.
I had an IDE DVD burner on my A1200T, was painfully slow, and not too reliable even when only burning CD-r's....
If you have the option, stick with SCSI....