Thanks for all the nice feedback!
Just a short note I forgot to mention in the intial post: the above listed scanner program switches off the Enhanced Shockburst feature of the nRF24L01+. As all libs available currently for nRF24L01+ do not initialize this feature of the chip correctly on start-up, you need to power down your circuit once before uploading and using another program/lib in order to reset the nRF24L01+. Otherwise programs which use the Enhanced Shockburst feature (basically all libs available for the nRF24L01+ do this) won't run.
The reason is that a simple reset (as happening for example when uploading new programs with the Arduino IDE) won't reset the nRF24L01+ to it's factory setting. However, simply unconnecting the power-supply and/or USB for a few seconds will do the trick.
Have fun! - cpixip