Need advise regarding small bookshelf monitor

If you mount in a bookshelf or entertainment system - do yourself a favor and install with a picture frame around the baffle and integrate into the walls in a flush mount fashion. If you do not then you will surely face strong edge diffraction issues. (This also means you need a forward facing reflex port in your choice of speaker and to fill any void space around the speaker with acoustic batting)

Alternativley use a wall bracket with a long extendable arm so that you can bring the speaker well forward from the cabinet shelves by a speaker length (even if you only do this for serious listening).

NHT Classic threes

How much do you want to spend?
Tobias speaks the truth, North Acoustics speakers are made for this type of application.

Pricing -- in the $3-500 range. Keep the recommendations coming as I'm not familiar with bookshelf speakers as have never peaked my interest -- these would be for my sisters' system & I don't have a clue as to what amp they are using -- probably along the big box store line; i.e., Yamaha, Pioneer, Sansui, etc.

$300 will get you a new pair of Epos ELS 3s. I actually have a pair at my office in a bookcase, they work quite well there. NAD receiver is the power.