another "Did I get a good deal" thread - 2007 loaded Prius

Hey all. I have spent the better part of this month lurking around these forums trying to absorb as much information as possible. This has to be the most useful information for any single car model on the internet! Seriously, Toyota should just direct any questions to this forum, because it has proved way more invaluable than actually talking to dealerships etc.

As soon as I started researching the Prius, I knew it was the car for me. Now I've just been trying to find the right deal! I have an appt. tomorrow to look at a loaded 2007 Prius - leather interior, nav, gps, JBL, etc. with 51k miles. It is listed for close to $18k, but the dealer has indicated they would go to $17k. (It also has brand new tires, but they are just standard Primewell tires and my research indicates these are pretty bargain low quality tires). Supposedly there are only minor exterior scratches which is to be expected on a used car. So, priuschatters, what say you? Would you pull the trigger or keep looking? Part of me is anxious to finally get a Prius, but I would rather be patient to make sure I'm getting an excellent deal.