I think a reasonably higher counter offer is always a good thing to do. If you really want to sell it and they won't budge on their initial offer, then you can always quickly tell them "Ok on the original offer." If they then say no, then they probably were'nt serious in the first place. Good luck.
Hark...I always counter as a rule of thumb...(bad origin that "rule of thumb" ...my wife hates it..lol)...but..I also always include the statement "please accept my counter offer of $whatever dollars...and feel free to renegotiate an offer based on that amount..sincerely..."
I've sold 4-6 .ws in the low-mid $xxx range pr month the last 3 months now, the majority on SEDO, and I've sold several in 2005 as well.
Highest offer in the high $xxx range (on SEDO), but I actually decided not to sell it for that since I'm sure that i can get more for it based on the offers I've received so far..