Just so you know, deep dish pizza is something that basically came along in the 80's in the downtown area, and was mainly eaten by tourists. It then became associated with Chicago by the tourists, and eventually the last decade or so, the young people in Chicago who don't know better have come to embrace it as "Chicago Style". The national media and culinary blogosphere has reinforced the idea, coincidently during the last decade or so as well.
But thin pizza, similar to NY style, but often a little thinner and more crispy, usually cut in squares (bar cut), has been the original pizza of Chicagoans for many decades, and indeed is still the most popular by far in the neighborhoods. Also to note, deep dish made quicker and stronger inroads on the North-side, and has it's most resistance on the South-side where it's still quite rare, even if it's getting more known.
Take a look at my post #63 below, Rev, where I include a picture of what I'm talking about here.
DP