Tell him you aren't actually planning to sell it. This way you will have an upper hand. Then ask him to make the best offer he can give so you can consider it. From there its up to you. If you think it's a great offer take it. Usually you can try to ask about 20% to 50% more of what he quoted. However, if you ask for too much more it might scare him off. Hope it helps.
Yes, definitely do not be the first to name a price. You want the potential buyer to name the first number.
I agree, try to maintain as much of an advantage as possible. Begin talking and ask him to quote a price. Once you ask DONT SAY A WORD, who ever breaks the silence first will lose the battle. Its a common negotiating/sales technique.
ok now... my opinion is really different: SELL IT as soon as possible. the guy could easily take .net,.org,.co.uk,.us as free Reg for just 10$ so if he offers you 20-30$ i'd sell it. the domain is not too old [2 months from what i see] and it's not too great :| so, my tip: SELL IT!