From the original list of hotels above this one:
... is not only the highest rated, gets 4.5/5.0 TA rating, but is also the least expensive. So why not this one??
I have stayed here and it was a very nice hotel, imo. It's about a 25-30 minute walk to Millennium Park so i wouldn't want to stay too much further north than here, but it's a very nice walk since you're basically passing all of the stores/shops of Michigan Avenue along the way.
I don't know specific parking garages nearby but i'm sure you'll find one separate from the hotel (parking at any hotel in the city will be expensive... a private garage less so), but to re-iterate, i wouldn't focus on the parking as there are garages all over the city. If you really need to watch your budget and the parking expensive is going to be 'make or break', you can always drop one person off at the hotel with luggage and have them check-in while the other person goes and parks the car at a more remote location with the cheapest parking (and the walks or takes a bus back to the hotel)... assuming you're not going to need your vehicle until you depart the city (at which point you do the same in reverse... go and retrieve the car while the other person checks out of the hotel and waits in the lobby with the luggage).
If you do end up at the Sofitel there is an excellent Lou Malnati's deep dish pizza place that is an easy walk and for a 'high end' meal Gibson's is right down the block as well.
Please remember to return to BetterBidding and use the PRICELINE and HOTWIRE links on the board to begin your travel purchases... or thru our sister site MAPSandHOTELS.com for your regular rate purchases.
Let us know what you decide and how it goes or if we can be of further help.