Steven - I'd wait about 14 days, no more. (eBay rules require payment within 7 days, it used to be 10 days). The amount of the sale, and the buyers feedback would have no bearing what-so-ever for me. You can recover SOME (the final value fee) of your eBay fees for the auction in question, by using eBay's Resolution Center. I recommend it:

http://pages.ebay.com/help/sell/unpaid-items.html

Mark's post is correct, sellers can no longer leave negative feedback, which you were not going to do anyway.