I agree, it's a good topic - or even just "ground" in general.
Why would you need a TL431 for a virtual ground? That actually seems rather undesirable to me - you want it to track the midpoint between the rails. A voltage divider like Dave used ought to do just fine.
If you don't care about power consumption you don't need an IC at all - a voltage divider with a decoupling cap will do for many applications. The divider has to be rather stiff, though. The op amp, configured as a buffer, allowed him to use huge resistor values to conserve power.