Well Predator, I wish I had this secret to negotiating that I could share, but the truth is, this was just a very motivated end-user. In fact, he only made one bid, and that was 100k. Most will think I should have countered, being that it was his first offer, but with Sedo it is a risky situation allowing yourself to ask for to much since you may never hear from the buyer again.
Bottom line: I was happy with the offered amount and accepted.
I paid in the low five figures for the name. Not many would have paid what I did based off of the appraisals I got.