Just bought a 2011 WRX (non STi) a few weeks ago. Planning to get all-season tires (I live near Chicago) and will not need the OEM Dunlop summer performance tires (size 235/45-17).
Tirerack.com sells these for 225 a piece. I have about 600 - something miles on them at the moment. Not sure what to price them at, and will consider any serious offer.