I'm also inclined to agree. The only other common spider that large or larger are fishing spiders normally found near rivers and streams.
Note to the petitioner: next time photograph your spider topside up. :>)
Actually, that IS the top side of the spider.
The legs were pulled up and I didn't really want to reach down there and straighten them out.
It was still moving a bit.
Here is a site where people try to identify each other's spiders. Although hosted in Australia, people also post from U.S.