2010 MBA Fully loaded - how much is it worth? where to sell?

Most recent eBay completed listings for late-2010 13"s with 2.13/4GB/256GB:

$605 (Gazelle)
http://www.ebay.com/itm/Apple-MacBo...06518929?pt=Apple_Laptops&hash=item5af1f67a91

$699
http://www.ebay.com/itm/Apple-MacBo...51447762?pt=Apple_Laptops&hash=item2a2d77bad2

$717
http://www.ebay.com/itm/Apple-MacBo...49614957?pt=Apple_Laptops&hash=item232b42366d

$605 (Gazelle)
http://www.ebay.com/itm/Apple-MacBo...85927373?pt=Apple_Laptops&hash=item35c7d58acd

$725 (Applecare)
http://www.ebay.com/itm/MacBook-Air...44737694?pt=Apple_Laptops&hash=item27d30f929e

$690
http://www.ebay.com/itm/Apple-MacBo...80533565?pt=Apple_Laptops&hash=item35c7833d3d

$750
http://www.ebay.com/itm/Apple-MacBo...12915630?pt=Apple_Laptops&hash=item3cd180c7ae

$800
http://www.ebay.com/itm/APPLE-MACBO...49655100?pt=Apple_Laptops&hash=item53f865033c

$725
http://www.ebay.com/itm/Apple-MacBo...21573403?pt=Apple_Laptops&hash=item4ac4565a1b

$699 (Applecare)
http://www.ebay.com/itm/Apple-MacBo...21573403?pt=Apple_Laptops&hash=item4ac4565a1b

$600
http://www.ebay.com/itm/Apple-MacBo...22807068?pt=Apple_Laptops&hash=item2ec7eebb1c

$725 (Applecare)
http://www.ebay.com/itm/Apple-MacBo...70564202?pt=Apple_Laptops&hash=item20d2801a6a

$799 (Applecare)
http://www.ebay.com/itm/Apple-MacBo...03642544?pt=Apple_Laptops&hash=item1c3256efb0

$607 (Gazelle)
http://www.ebay.com/itm/Apple-MacBo...89997403?pt=Apple_Laptops&hash=item5af0fa615b

$695
http://www.ebay.com/itm/Apple-MacBo...00962399?pt=Apple_Laptops&hash=item1e7a4e2c5f

$604 (Gazelle)
http://www.ebay.com/itm/Apple-MacBo...08423567?pt=Apple_Laptops&hash=item5655e7848f

$700
http://www.ebay.com/itm/13-Apple-Ma...63052750?pt=Apple_Laptops&hash=item20d20d7cce

$690 (Applecare)
http://www.ebay.com/itm/Apple-MacBo...12968168?pt=Apple_Laptops&hash=item257d1eeae8

$678 (Gazelle)
http://www.ebay.com/itm/Apple-MacBo...03363485?pt=Apple_Laptops&hash=item56559a4e9d

$899
http://www.ebay.com/itm/Apple-MacBo...55222730?pt=Apple_Laptops&hash=item19db6837ca

$699
http://www.ebay.com/itm/Apple-MacBo...91438644?pt=Apple_Laptops&hash=item41725af834

$799
http://www.ebay.com/itm/APPLE-MACBO...97547302?pt=Apple_Laptops&hash=item1c31f9ee26

$729
http://www.ebay.com/itm/Apple-MacBo...10454518?pt=Apple_Laptops&hash=item4ac3acb0f6

$799
http://www.ebay.com/itm/MC905LL-A-A...55062498?pt=Apple_Laptops&hash=item20d19390e2

$645 (Gazelle)
http://www.ebay.com/itm/Apple-MacBo...71519951?pt=Apple_Laptops&hash=item5aefe06fcf

$699
http://www.ebay.com/itm/Apple-MacBo...09929401?pt=Apple_Laptops&hash=item338123a6b9

$619 (Gazelle)
http://www.ebay.com/itm/Apple-MacBo...74581553?pt=Apple_Laptops&hash=item5af00f2731

$799
http://www.ebay.com/itm/Apple-Macbo...16881787?pt=Apple_Laptops&hash=item2a2b684b7b

$641 (Gazelle)
http://www.ebay.com/itm/Apple-MacBo...60889451?pt=Apple_Laptops&hash=item35c6577e6b

Average: $705
Average w/Applecare: $728
Average of non-Gazelle listings: $735
~ 65% chance a non-Gazelle listing will be within the $122 window of $674-796

[Gazelle being that electronics trade-in service; many of their listings had physical damage like scratches or dings. Also, just anecdotally, I tend to think that buyers will also pay more when they buy from private sellers rather than from large entities in the business of selling used electronics.]

I've had good luck selling on eBay. You can generally ensure that your listing will be on the upper end of that price range by using clear and visually pleasing images, making sure your description is grammatically correct and articulate, and timing the ending of your listing so that it falls around 9pm to 11pm on the east coast on a Sunday (when people are sitting around with nothing to do and have nothing to distract them from remembering to bid on your auction).

You can also get a rough idea on price through http://www.mac2sell.net/