When I lived near the airport I made an ACARS monitoring box with the B200 and GR. Had a bunch of fun analyzing engine performance data and the funny messages going back and forth. Travelling with my rtlsdr has saved my butt a few times. Always nice being the first to know that a flight has been cancelled.
I will admit that I actually listened to the original system a lot with headphones, so I had every reason to fine-tune it until it sounded as awesome as possible. If you go back far enough into 2011, you can find a bunch of calls with terrible audio before I figured out the finer points of squelch, tuning errors, and 48 vs. 44.1 kHz :-)
I haven't decided whether it's worth building another system now that I have time to actually listen again. Hmm...