I feel your pain. In the past year, I spent over $1K on SDS100 (with enhancements) and a 536HP to be able to monitor our Statewide Starcom21 P25 trunked system. Most, if not all, law enforcement, fire, and EMS agencies will be on this system which has been up and running for 10 years. Motorola owns it, and agencies pay xx dollars for the usage of their units on the system.
Fortunately, the agencies I monitor are switching over to TDMA Phase 2 from FDMA. This is all well and good, and for now, the only comms that are encrypted are certain surveillance and drug enforcement agencies in DuPage County. Main dispatch talk groups are in the clear, so we can hear what's going on around us.
I have been informed that DU-COMM and ACDC dispatch centers will eventually encrypt all communications, possibly within the next two years. Cook County agency talk groups are all encrypted and will remain that way permanently. I know it's expected and will happen in DuPage County, so I'm enjoying what I can for the time being. Then there will be no more except for the multi-cast VHF channels tied to fire dispatch talk groups.
For further details, if you're not familiar with Starcom21 in Illinois, here's the WiKi for them:
wiki.radioreference.com