What's my Panny worth?  

I'm pulling the trigger on a Pioneer 940HD to replace my (almost) 3 years old Panasonic TH-37PA20. The Panny is in excellent shape with all manuals, remote, and the interior box, etc. present. I'd like to sell the Panny if possible as I have no-where for it to go once the Pioneer gets here.
Anyone give me any pointers on what I might ask for it, and realistically accept?
TIA,
Bish