I think $1,000 initial offer is good if the domain is good enough and is not being used by the owner. If the seller is serious about selling the domain he will take your offer seriously and may quote his price if he feels he should get more. You can always offer more later.

I own a six-letter .com domain - guzloo.com. It is easy to pronounce, spell and remember and will suit for fun or gaming sites. If someone comes up with a $1000 initial offer I would think about selling it because I don't intend to use it in any of my projects in foreseeable future.