All of them are important though. I think writing of quality tops the other two because I won't even begin to read a story if the quality of writing is low, but character and story development is what keeps people reading.

All 3 are important but I believe writers will favour one over the others and I often favour the last option more than the first two EVEN THO I do keep in mind for the first two when writing

actually all three are equally important, depending on the writer and how they wanna do it.
but then again, a lot of people enjoy things base upon what they are actually reading. XD