FXI apparently has his head shoved up his ass again, so i will explain what he FORGOT to mention. now, as you can tell, most drives are going IDE, with only a few staying SCSI. IDE drives aren't necessarily worse than SCSI, just different.
the only thing you can't do with an IDE writer that you can do with SCSI is to be running programs in the background. SCSI drives have less chance of having a buffer underrun, but IDE drives can be just as stable and fast if you close the open programs.
the other myth is that SCSI drives are faster than IDE drives. this is also not true. an 8x drive, whether it is SCSI or IDE, will still write at 8x. like i said before, the only real difference in terms of the software-side-of-things is the stability. the internal connection is also slightly different, with IDE drives being easier to install.
i hope i've cleared up the myths for you, so now you can go out and buy that IDE HP drive with confidence.