I personally wouldn't order from Amazon directly without being a Prime member. I have had Amazon sit on in-stock items for up to two weeks before shipping out. With Prime they always arrive in two days. The various people selling through Amazon are a bit faster. Of course I'm impatient and want to play with my new stuff.
Not much has changed since this thread was started in 2010.
I bought a used Nikon AF 24-85mm f/2.8-4.0D IF Zoom Nikkor Lens through Amazon.com recently.
The seller was a business in Korea.
The price of the lens was lower than normal, included shipping, I got the lens in just 5 days, and it was exactly as described.