Klipsch is total garbage. Especially their THX 5.1 solution. It doesn't stand a chance against the 5500. Go with Logitech. There are some minor faults like with an unshielded sub.. but you can find a way putting it far from the computer and monitor. Klipsch doesn't sound better. Not in a trillion years. In fact having a shielded sub, can cause it to be distorted. This is why Logitech often wins on CNET over Klipsch.
You either can sacrifice sound quality and get Klipsch and have the magnetic shielding, or go with better sound quality.