Now let's look at Cook County's returns, which can be tricky (especially when CNN omits information) because you have Chicago and Suburban Cook County to add together:
Pat Quinn (D) 883,450
Bill Brady (R) 395,071
Scott Lee Cohen (I) 51,527
Rich Whitney (G) 34,421
Lex Green (L) 10,332
Over half of Quinn's vote total comes from Cook County alone. Quinn only managed to win two other counties (St. Clair County by 1,368 votes; Alexander County by 122 votes). If we remove Cook County from the results this is the result:
Bill Brady (R) 1,306,149
Pat Quinn (D) 836,872
Scott Lee Cohen (I) 82,612
Rich Whitney (G) 65,071
Lex Green (L) 23,938
Without Cook County, the race is a Brady rout. Even adding 100% of the Cohen, Whitney, and Green votes (171,567) to Quinn's total (836,872) results in a solid Brady win of Brady (R) 1,306,149 to Quinn (D) 1,008,439.
Quinn's win is a combination of City of Chicago-Cook County Democrats coming out too strong. Suburban Cook, the collar counties and downstate Republicans just could not make up the massive vote difference