if you wanted to branch out into hifi i'd recommend the energy take classic 5.1 ($300) + a 5.1 receiver ($100-200).
benefits over computer speakers?
-can use longer wires and route them through walls (normal speaker wire). the z906 will have them all on the floor if you wanted to put it in the corners if the cables are even long enough.
-improvement in sound quality over pc speakers
-if you get a decent receiver, its upgradeable to better speakers in the future.
-can use it easily with just about any source with a quick knob-turn to chance sources.
or, if you have a larger budget (or smaller) there are certainly other options available to you.
i personally use a 5.1 home theater system (though much more costly than what i recommended above) and love it. a definite improvement over computer speakers for the money (though the logitechs arent bad for pc speakers). if you care to see the setup its in my build photos in signature link, info on what i use is in list when you hover over avatars.
given that you said "all around your room" i think a traditional home theater set is going to be much cleaner though this is your choice to make.
if you want some more in depth information i'd suggest giving us such info as country of origin, budget, what you need to use the speakers for, upgade plans, a general idea how you want to route wires/place speakers, etcetera.
edit: monoprice 10565 is basically the same thing as the energy system (just unbranded) for $120 less.