I personally don't think preserving value is your goal as you wouldn't get exactly a fortune for the bike. A smaller version didn't sell for the seller's $175 price on eBay: http://cgi.ebay.com/TREK-560-SERIES-...QQcmdZViewItem

If it's your size, paint it your favorite color and ride the heck out of it. Heck, chop off the brazeons and make it a fixed gear. The most important thing is to ride.

Neal