Yes, getting the Boston speakers you mentioned, or something similar, should make a significent (sp?) difference for music.
Besides playing somewhat lower & higher frequencies, you should see an improvement in the mid-bass. When you compare, don't just listen for the highs & lows; look at the area just above the bass - the Boston speakers should produce a more "full" sound.
I listened to a pair of Boston Acoustics VRB bookshelves recently, & liked them.