Fitzpatricks is no longer Fitzpatrick's, it's an Affinia now. Last time I looked at it the restaurant was closed for renovations as was the bar so check to see if that's done. Having said all that I've never stayed there but here's my take on the hotels I have stayed in in Chicago.
Hyatt. Location ok. Lobby, smelly and noisy. Corridoors dated, rooms small.
James. Very funky and trendy. Good location. Maybe too trendy, especially for Christmas?
Hilton. Awful location. Rooms dated and smelly. Would not recommend.
Sheraton. Good location, great rooms, fab beds, friendly staff. Recommend this one but my favourite is...
The Intercontinental. Best location right on Michigan Avenue North. Lovely rooms, felt a little more special than the others. Would be perfect for Christmas IMO
Can't remember what the taxi fare is from the airport but it's not crazy.
December will be very very cold and there is a serious risk of airport issues, snow closes the airports fairly often in winter.
All that said, I love Chicago!