You might think now that most of us don't have books, that would free up a lot of space on our shelves for all kinds of stuff, including bookshelf speakers! That's why I first have to reveal a dirty little secret about bookshelf speakers: they don't sound best on bookshelves!
Most competently designed bookshelf speakers sound better, more spacious and open when placed a foot or so away from the wall behind them, with the speaker's tweeter at about the height of a seated listener's ears. For the best possible sound, put 'em on speaker stands. That's ideal, but if you need to mount the speakers on a wall bracket, high up or low down, that's OK too. So only as a last resort should you even think about putting any speaker on a bookshelf.
This is a roundup of stereo speakers you hook up to a receiver or integrated amplifier; if you're looking for, aka nearfield speakers, check the list I posted earlier this year.
Click on any image below to view the complete slideshow of my top 10 bookshelf speakers.