How much over the value of a house would you pay for the right house?

[Flump9]

Trying to keep details vague, there is a house that would be perfect and the opportunity to buy similar unlikely in the future. The owner might be interested to sell for the right price but this would be more than the market value. No mortgage so not held back by valuation it would just be what we were willing to pay above the value. We are not likely to sell for a very long time if ever if we bought it so don't need to recoup the price any time soon. I know a lot of houses are selling for more than asking currently so we don't mind paying over it's just where to draw the line.

But what is the 'market'? I sometimes do not get how valuers come to their decisions - I had a bidding war on one house with both going over ask, but the mortgage valuer marked it down, but if a house is worth what someone will pay for it, and in this case two separate parties, surely that is more indicative of its worth than what a similar house sold for six months ago?
Anyway, are you in competition with anyone for this property? Or is it that it is not on the market at all? How has the 'value' been decided - estate agents?
Negotiating a purchase or sale is not easy- I believe both parties feel that they could have got it cheaper or should have held out for more. It is even more difficult if it's an off market sale - you really feel in the dark.
If you've looked at a number of houses you must have an idea of it's value, which may not be the same as what it is worth to you - but only you can determine that. 5% max over 'value' if it truly is your dream home..

A house (or anything really) is worth what someone will pay for it - so whatever you would pay is its value!

I would pay over if I had the means an loved the house, and may stay there forever. Why not go by what thy ask an then decide (gut instinct / how confirtable you feel) with that figure? If it does feel wrong you ca nalways counter-offer.
Obviously see the sold prices nearby so it's in ballpark, maybe 5-10% over depending on the value.

*comfortable (and the rest of the typos!)