I hate to say this, but it depends on what each 5V is used for.
An analog 5V rail will benefit from being heavily filtered, and generated from a LDO/Regulator. In my experience, analog rails are quite light in current compared to most digital rails.
Your digital rails, typically higher in current can be done with a good buck converter. (Switch mode DC/DC Buck). I'd strongly suggest you make sure it's running at a decent high speed (100kHz +). This will give you two benefits, the switching current (per switching instance) will be lower, happen out of audio band, and be easier to filter out with an LC circuit.
After 15 years in this business, I've always thought it was a miracle that system designers were able to get the performance they got from converter boxes. There are so many variables to fight - clean power, accurate clocking, front end signal conditioning. Then add the rest of the fun - buttons and switches for user interface, data conversion to s/pdif, adat, usb etc.
Having written all of that, i also have to say - just do it. Build it, try it, love it, tweak it. You'll have achieved more than most of us on here griping on about converters.