In the UK I've seen them go for between £50 and £100, depending on how many people there were bidding. Personally I quite like the paint job, but it may knock the value a little.
No keyboard or mouse could put quite few people off so i would recommend trying to clean up the keyboard and mouse if possible. It's better to sell a complete working system than leave the buyer to find the missing bits.
If it's maximum money you're after you might be able to get more if you took some of the ZIPs out and sold them separately.
