Hard to tell for sure, but I'd lean towards Dolomedes tenebrosus - the striped legs, angular abdomen and the large size, plus the fact that it was found in your basement. It's a common upland type of fishing spider that's moved over into sort of wolf spider behavior territory. Harmless to us, like almost all spiders, but loves crunching down on a tasty beetle snack.

http://bugguide.net/node/view/2011

Found in my basement tonight. I live in Indiana 30 mins. outside Chicago.