Buyer checklist: Ensure a seamless transition to your new home

UTILITIES: 

Electricity
You can use ComEd to supply and delivery your electricity, or you can choose an alternate supplier--though ComEd will still be used for delivery.
Information regarding green providers here.
Start/stop/move service here.  

Gas
The metropolitan area of Chicago uses Peoples Gas. You can use Peoples Gas to supply and deliver gas, or opt for an Alternative Gas Supplier, though Peoples Gas will still deliver.
Information regarding Alternative Gas Suppliers here
Start/stop/move service here

Cable
If you are moving to a condo, your association may have a preferred provider. Contact your property manager or board president.

Mail
orward the mail to your new address.
Update information here, or by completing a change of address form at any post office. 

TAXES:

Real Estate Taxes
Even if your lender pays your real estate taxes from an escrow account, you should double check that your taxes have been paid. The due date for the first installment (for the first half of the year prior), is always due on the first business day in March. The due date for the second installment varies, but you can check on that date as it updates here

Exemptions
A number of tax exemptions are available for home owners, most notably the Homeowners Exemption, which can save up to $2,000/year.
Information regarding criteria here
To apply, here.  

Appeals
Real estate taxes in Cook County are based off of the valuation of your property. As a homeowner, you may feel that your valuation versus comparable properties is skewed high, in which case you can appeal your valuation. Many condo associations apply collectively, whereas single family home owners are required to apply individually.
Deadlines here
Paperwork here
To apply, here

CAR:

Driver’s license
While updating your address on your driver’s license is not required, the DMV does require that you update your address for their records within 10 days of moving. You can make the change online, by mail or in person.
Update here.  

Vehicle registration
Your vehicle registration address must be updated separately within 10 business days.
Update here