advice sought -- what to place in Dock I

[paul@research.att.com (Paul Krzyzanowski)]

I would like to add a CD as well as a SCSI disk to my
ThinkPad.  Only one device will fit within the docking
station (officially).  The questions I have are:
   - has anybody tried attaching a non-IBM CD-rom drive
     either internally or externally?
     My inclination is to get an external NEC 3xe triple
     speed drive (which costs roughly the same as the
     $600 IBM double speed one for the ThinkPad).
   - are there particular advantages to having an IBM
     CD-rom and are there particular advantages to having an
     internal one (other than the portability)? 
     Specifically,  the internal CD-rom installation includes
     audio cable hook-up.  What features does that enable?

Any comments or suggestions will be most appreciated.

Thanks!

Paul Krzyzanowski
paul@research.att.com