That's good Rick, but never forget that those linear regulators have a large voltage drop, 1-2 volts.
Some of those 6v unregulated power supplies that are 9.8-12v with no load, can get pretty close to 6v with just 50-100mA. If your project needs 5v and uses more than that, then your LM317 will have too little input voltage.
There's a huge selection of LDO chips (low drop linear regulators) which are also cheap.
For example (surface mount, but through hole to-220 and similar versions available)
up to 10v input, 300mA output, 0.2v voltage drop at 100mA :
http://uk.farnell.com/microchip/mcp1802t-5002i-ot/ic-ldo-5v-300ma-sot-23-5/dp/1578372up to 16v input, 300mA, 0.3v voltage drop at 300mA :
http://uk.farnell.com/microchip/mcp1755st-5002e-db/ldo-0-3vdo-0-3a-5v-2-3sot223/dp/2306611So you could basically even take 5v from a usb charger as input and get 4.8v+ at the output, which is close enough to 5v for a microcontroller and various 5v stuff to work without problems.But, you'd protect the devices from usb chargers that output 5.6v or thereabouts at low loads.
Really, these regulators are cheap in volume and just as easy to use as the classics.