The lifelike reproduction of vocals is by far my first priority. If a loudspeaker fails that test it is immediately eliminated, and most are (vowel coloration---though significantly improved since the early days of hi-fi---remains a problem). Closely following is the reproduction of instrumental timbres, especially acoustic string instruments: guitar, dobro, mandolin, fiddle, upright bass, piano (yes, it is a string instrument ;-), and harpsichord.
As for "hi-fi effects", it is image size and scale. Most loudspeakers sound comically "small" to me, the image of a grand piano, for example, being reduced to a miniature of it’s actual size. It’s like watching a movie on your iPhone. Hearing a doll house-size musical picture immediately destroys the suspension of disbelief.