Hi,
My wife and I have used 3 different realtors over the past 3 years to purchase our properties. While they were honest, pleasant and professional, they could not be trusted to give accurate valuations. Don't use "comps," you're better off going to the courthouse or courthouse website and access the records yourself-you want the public records information for sales, not what the property is assessed at. If you think the realtor has as much on the line as you do, and is able to work as hard as you to deduce fair market value, you're a fool.
Disclaimer-we purchased two damaged foreclosures (our main house and a rental duplex), and a unique piece of land on the water, all in Florida during the down-turn. The realtors could not put together a rational price model because the properties were odd, damaged, or thinly traded. Ironically, because these assets were difficult to value, we were able to get our money's worth and more.
Trulia and the like are for entertainment purposes only...
Good luck!