$449 at Micro Center B&M.

$420 @ Apple as a refurb, but Apple refurbs are every bit as good as new.

http://store.apple.com/us/product/FC769LL/A

MicroCenter B&M will charge you local sales tax! The lowest sales tax among MicroCenter local stores is the one in North Jersey, 3.5%, adding the sales tax, this would be $464.7, a few dollars more than the eBay deal. FYI.

#3, so will Apple direct.

Not that Apple is the only product doing this, but still worth reading

http://www.nytimes.com/2012/01/26/business/ieconomy-applebaconpad-and-the-human-costs-for-workerbaconn-china.html

I bought one from Microcenter because they were the cheapest option. It worked out well, but be sure you will not return it. There is a 15% restocking fee.
The refurb looks like a good option to me. You get a new battery and new shell and the same warranty as a new one.