If I were you I would go GA Tech computing. UIUC CS is known for machine learning, operating systems and distributed computing. They do not have strong HCI side.
My top choice for HCI would be GATech college of computing, CMU HCII, UW-Seattle CS (not HCDE, not iSchool), MIT Media lab, Stanford, Cornell iSchool, Penn State IST, Virginia Tech IST, UCIrvine., UC Berkeley iSchool, Indiana University.
http://www.quora.com/What-are-the-best-graduate-programs-for-HCI-in-the-United-States-and-Europe