Probably right around 2 grand.... which I'll admit is WAAAY more than the blue book value, but is the same amount I paid for it about 5 months ago.
The problem with motorcycles (as I see it) is that you can't find a good, running bike in good mechanical and cosmetic condition with fairings and a clean title for under $2000.
Anyways, the '89 is the only model year with clip-ons instead of handlebars... so it is more crotch-rockety than newer GS500's. Although the age of the bike lowers the cost of insurance... it also makes full coverage a bad deal since paying 2 years coverage is like buying the bike all over again (based on blue book value).
I love this bike. Its small, light and VERY flickable. If it had 30 more hp then i'd keep it forever (it has ~40hp). I'm still debating wether I really want to upgrade or not :-/