I'm not sure these should be blatantly merged, as "suspend" by itself has two meanings.
sleep (Windows / common name) / suspend-to-ram (technical name) is where almost all the hardware is turned off, but the RAM modules are still continuously refreshed so that they do not lose their contents
hibernate (Windows / common name) / suspend-to-disk (technical name) is where the contents of the RAM modules are written out to a file on the harddrive, and then the system is turned completely off.
I would instead suggest creating the above synonyms, and retagging the suspend questions to one or the other, as appropriate.
sleepwas trivial too. As Mechanical Snail on the other question pointed out, the different tags are all used to mean the same thing, even if there is a technical difference between them.