If you’re looking for a desktop power supply for your electronics workbench, this tutorial video shows you how to turn a computer PSU into a desktop power supply.
In the above video the guys at JumperOneTV show us how to make a desktop power supply. As an addendum to the video; they note in the comments section on the YouTube video that they were wearing gloves for the drilling and that they did a very thorough job cleaning out any loose metal shavings with an air compressor. If you wanted to play it even safer (and you should!) you would remove the circuit board from the enclosure before doing any drilling.
Converting an ATX Power Supply to a Lab Bench Power Supply [JumperOneTV via Make]