Thinly veiled WDIS?
Personally, I think Chicago, while a spectacular defense, is sometimes overrated from a fantasy perspective. They've given up decent yardage, though are tougher on scores. Certainly game dynamics and circumstances dictate some of this.
There are plenty of people they've shut down (Morris, Edge), but also plenty of people who had some of their best games (from a fantasy perspective) against Chicago.
Gore had 111 yards on just 12 carries (most of which came on 3 big runs). Ronnie Brown had 157 yards. Ahman Green managed 110 yards on just 20 carries. Even Kevin Jones, who didn't really get started yet, managed 82 total yards. OF course, Leinart also had arguably his best game against the vaunted Chicago defense.
At the same time, Chicago has the ability to score - even if they give up 30 points (assuming you get 0 or even -1 for that), Most leagues I've seen give something between 10-15 pts for a shutout, 7 fantasy points if they hold under 10 pts - and 1-2 pts for every sacks, int, and fumble recovery. Consider also that the Bears defense definitely has the ability to convert those into scores (i.e., an additional 6 pts), and I think it's clear you play both.
Denver's defense is great, but not as good from a fantasy perspective.
you play who you would play if they weren't playing each other. unless you have more powers than kupcho or i do. in which case, you should just play the lottery. 
