http://www.cmap.illinois.gov/LandUseInventory2005.aspx

This is one of the most popular datasets among urban planning students! It’s a land use dataset of the seven-county region of northeastern Illinois. Northeastern Illinois is comprised of Cook, DuPage, Kane, Kendall, Lake, McHenry and Will County. The data is available both in shapefiles and ArcGIS personal geodatabase formats. Land use is aggregated to 49 categories, and was created using black and white orthorectificed aerial photography that was captured in April, 2005.

Additionally, CMAP (formerly known as NIPC & CATS) released a revised (Version 2.1) 2001 Land-use Inventory, which can be used for any comparative studies with the 2005 Inventory.

On this site, find a link to their FTP site – registration is required (but free!)

For more sources for landuse data, see under Landuse & Landcover, US category.