My personal favorite in Chicago for thin crust pizza is Cafe Luigi at 2548 N. Clark. Just south of Clark & Wrightwood. I grew up in NY and it reminds me of the pizza from there. Avoid the thick crust at Cafe Luigi, not that good, but the thin crust is excellent!

....hmmm almost 5:00 and I'm getting hungry...might be time to head to Cafe Luigi tonight.