It depends on so very many things...
What's the market like for homes in your area now- do homes generally sell quickly after going on the market?
I would base my offer on the worth of the home, rather than the buyer's asking price. What have similar homes sold for lately?
Be aware that the appraisal on record at the county auditor's website was for the purpose of establishing taxes, not for establishing resale value. The county's appraisal is often not a good point of reference...
In general, home sellers are most optimistic when a home has just been listed, and will often expect to get the asking price, or very close to it. If a home has been on the market for a while, they are often more desperate, and more willing to entertain offers substantially lower than the asking price.
All that said, every seller has a different set of circumstances and expectations.
If you make an offer for 95% of the asking price, the seller could either: accept the offer on the spot, counter with their own proposal, or ignore your offer as ridiculous. You'll have to determine what that house is worth to you, and make an offer that you can live with.