It's very simple:
If you're looking fore a fully featured drive, one with a headphone jack in the front, or if you're more adventurous, forward back buttons, then a Plextor or Yamaha SCSI, though the Yamaha SCSI drives are not as reliable. Be prepared to pay a lot of money.
If you're a more practical person, and you want something inexpensive that will cover all your bases, then you want either the LG GSA-H10x or GSA-H12x, both models being Renesas-based (as opposed to the lousy Panasonic varieties).
These drives don't need their capacitors changed, all they need is a belt cleaning or else the tray won't open.
These drives have excellent compatibility, they read (and write) everything you throw at them, and they are very inexpensive.
So be practical and get one of those, or you can shop around for old contraptions which may or may not work. Personally, I purchased a Yamaha SCSI drive for my Tualatin build, but that's because I need something that can write to very old media.