My stock tires are 215's. I contemplated going up in width but the service guy gave me a long speech about how cars come off the production line with too much tire to begin with and with the poor condition of the stock Good-for-a-years and this being the only place that could get me the Kumho's I didn't rebut so I stuck with the the 215's.
BTW- I posted this a while back, It shows a comparison of tire sizes if you are considering going bigger.
Ejelta.com: Tire Size Calculator