recommendation for hifi bookshelf (eg 7"-18" high) stereo (not
surround sound)speakers $300-$500 USD based on trusted review sites or
hifi magazine site reviews. For listening to music at home (NOT hard
rock or rap or heavy bass stuff, so midrange is more important than
booming bass) Looking for best sound quality or 'best value'
recommendation for my money. Audio quality for music/vocals is the
main priority and often for use at low volume rather than the need to
'fill the room' (or those of neighbours) so if something performs
poorly at low volume it wouldn't be suitable. Looking for somewhat of
a conensus of opinions from multiple reviewers or magazine sites as to
the best sounding speakers in this price range.

Get a used Bose Acoustimass system.

whatever you do, do NOT get Bose for ANY price. If you don't believe
me, visit your local pro audio store and ask them what they think of
Bose. Anyway, your 300-500 range covers a lot of speakers. It's the
most competitive range in audio business - low-end of consumer speaker
market. Your best bet is Paradigm or PSB. Others to audition: Energy,
Boston Acoustics, Definitive. Mirage, Athena, Energy and Paradigm are
made by the same set of people. All consumer speakers come in series
spread low-end (300-500) to mid-range (2-10k) and you have to audition
them yourself. Take this as an initial shopping list and go have a
listen.