I love it when people say "UNIQUE DOMAIN!!!!" or "ONE OF A KIND DOMAIN!!" aren't they all?
DO NOT QUOTE HISTORICAL SALES DATA!
Those names sold at the prices they sold for because someone else was willing to pay that amount of money. No matter what has sold, each individual name sold based on certain criteria the buyer was looking for. Each name has its own value and that value is an unknown until the name sells. What other names sell for in my opinion is totally 100% irrelevant to any other name, irregardless of extension. Each name is as individual and as unique unto itself because there is only one name in a particular extension. It is like a vanity license plate or social security number...there is only one of, it is unique, and can not be copied. That is why historical sales (especially in this economy) have absolutely no bearing on any name being sold today.
I have to slightly disagree with this. A couple of times in the past I've been able to use recent sales of similar domains (same domain, different TLD etc..) to justify a price way off what the other party was requesting (buying and selling). Each time the agreed price was a lot closer to my figure than their's.
Recent sales data on very similar domains is not a bad thing to look at but make sure they are very similar (like I said, same domain, different TLD).
Leave out all irrelevant data - yes, we know what a LLL combination can stand for and we can easily look up search volume.
Don't B.S. us, we'll call you out on it - and it's been done before many times. While most people don't care about traffic if you're claiming hundreds of visitors a day on your 3 month old hand reg, be able and willing to back up that claim with proof, including sources, etc..
Keep the price reasonable but leave room to negotiate.