Yeah.. I just leave the box itself on, and turn off the monitors; that's just the rule of thumb I've been thought to help better manage electricity, and the life of your system. From what i've gathered power on / off / on / off isn't good for life of your system. Constant static power == yum.
Altec Lansing are nice, but For PC speakers I like Klipsch. The sound is rich as hell. Really smooth bass as well. The 2.1 Setup usually goes for 179.00 or so. But yeah, Totally worth it. Just ask my downstairs neighbors!