Well, the HarleyDental.co.uk from the same crap lot has been offered GBP 500 with a single outbound phone call ($650) .I think its worth more than 500. Harely Street in London is famous for dental and cosmetic clinics. I will wait for right offer.
One thing you might want to consider... The domain may well be worth more than GBP 500 to someone, but that buyer may take years to show - or may never show up at all. 500 is a nice return on a name you got for reg fee.
Taking the money now would allow you to acquire many more names and possibly make a much greater profit in the same timespan you spend waiting for the right buyer of HarleyDental.
For example, say you are waiting for GBP 1200, and it takes you 2 years to sell it (which isn't long at all in the scheme of things. You are up 1200 (minus reg fees) in 2 years.
But what if you took 500 now and got 3 or 4 slightly better names in the aftermarket? Any one of those could sell for GBP 2500 or so, without straining the buyer. You might actually be losing money by holding on to one domain trying to squeeze the best price out of it.
Of course, there is no way to know which way to go - so much is up to fate. But cash flow and opportunity costs need to be considered.
A lot depends on your circumstances and buying patterns, but if you need to sell a certain amount each year, in most cases it's better to take the cash in hand and reinvest. If you don't need the cash, then go ahead and hold out. If it's a name with a potentially massive upside, then hold out. But when a name has limited upside, I tend to prefer the cash in hand.