The Intel ATA drivers are fine for most situations, and is normal for the OS to recognise your drives as SCSI devices, particularly under Win2K. You might want to try the new beta 6.10 drivers, as they fix numerous problems with the previous 6.03 drivers.
Most of the problems with these Intel ATA drivers relate to ATAPI/IDE CDRWs, where systems with these drivers installed are unable to burn CDRs/CDRWs. Again, the new 6.10 drivers should fix most of these problems, again mostly with Win2K. Win9x seems fine in most cases. If you insist on using the Intel ATA drivers and you have problems with burning, change the maximum transfer rate using the Storage Companion to PIO Mode 4.
The Intel ATA drivers are NOT essential to the operation of your system, and you can get along fine without them, using the drivers provided by Microsoft as part of the OS. Just remember to turn on DMA for best performance.