i own z680, although it's a old model but it does play pretty good. Frankly i would say speaker is something will last for long time and if you really want to invest, invest in the one that really got some quality.

noted, creative speakers tend to blow amp but for clarity, i think they are the best. logitech heavy bass, personal preference by lower down the bass from the control unit and tweak from your player's EQ (if you are using pc), the sound will turn out pretty sweet. Aego M got good reviews but sadly only 2.1 and it cost a lot.