I bought an X-530 system from Sam's Club for my studio yesterday for $57. They had the X-560 system, which has similar specs to the X-530 system, for around the same price. The X-530 had the center speaker and the speakers were wall-mountable.

I needed a surround-sound compatible speaker system for my computer just to help me with surround mixing but I'll use my existing studio monitors for the actual production monitoring. I had to turn the sub all the way to it's lowest setting and then use my computer's software EQ to roll off even more bass before the system sounded anywhere near balanced. The Logitech speaker systems all seem to suffer from nearly uncontrollable bass but they are cheap at least.