This thread got me looking into the AirNav, SBS BaseStation and the Mode-S Beast, but all of those seemed so cost-prohibitive. Then I stumble across a very low-cost alternative. The range is not as good, admittedly, as what 02blackss is getting with his AirNav setup, but for the cost I don't think I can complain.
I'm using an RTL2832U dongle with the supplied antenna. This USB stick is intended for receiving digital television signals, but with the free RTL1090 software and free Zadig drivers, it can be tuned to 1090MHz and receives Mode-S or Mode-A/C. I then have the free Virtual Radar Server listening to port 31001 (which is the broadcast port for RTL1090). VRS has a built-in web server so you can view plane plots with a web browser overlayed on a Google map. VRS can also rebroadcast the Mode-S and A/C signals on other ports in other formats (BaseStation and AVR, or simple pass-through). I have one feed going to PlanePlotter's 21-day trial, another to FlightRadar24's feeder server, and another feeding the free ADSBScope software, which is similar to PlanePlotter. I'm getting a range of 200+nm (record so far is 229nm). However, because I'm in an apartment building directionality is definitely an issue. I can see in a 180 degree arc to the south, but very, very little to the north. Below is a screenshot from ADSBScope showing the range "bloom."
Total cost: about $23 for the dongle off eBay (shipping included).
Rob