If you have a spare set of stock 18's seems like a no-brainer to me. Slap some blizzaks on em and call it good.
Blizzak LM-25 (closeouts) and LM-60 (new model) are avaliable in stock sizes. Most guys here go with 225/50-18 all around. I kept the stagger with 225/50 front, 245/45 rear.
AK's setup
My setup