Software-defined radio ideas

From twitter this past week, Tom Rondeau asked: "I'm giving a day-long lecture
on SDR. What would you want to hear about? I'm focusing on software and
processing."

Tom Rondeau is giving a talk with fred harris, a well-known DSP lecturer and
professor at SDSU.

Balister offered, "Explain the difference between a collection of functions that
do operations and a framework providing structure for using them."

What do you all think? What are the current concerns in software-defined radio
design? I have some ideas, but I'm very interested in what you all think.
 -Michelle W5NYV