Go to www.kbb.com
On the left side of the window, toward the bottom, click "Motorcycles"
Drill your way down to the year, make, and model. You will find a significant difference between the "Standard", "Icon" (Standard + computer, grip heat, CD changer...), and "Custom" (Icon + Chrome doo-dads).
If this is from a dealer, use the retail price. My rule of thumb for buying from a private party is that fair market value is about half-way between trade-in and retail. Adjust this for mileage, condition, and regional variation/market demand.
For another opinion, here is Motorcycle Consumer News' value guide from last Novemer. Again, adjust for condition and regional variation.
Now that we are in 2007, psychologically, the bike is a year older, so the market value will be down a smidgen. IMHO, this is purely a psychological issue. OTOH, anything is worth what someone else is willing to pay for it.
Do you have the cash? If this is a private party sale, can you get the bike to a mechanic for a pre-purchase inspection?
I can't tell you how much $ the 60K service should run... the 2000 I just bought only has 28K on the clock