Logitech Z-5500 or Gigaworks G550W Pro Gamer???

Hi all,
I currently own a set of Megaworks 550 THX speakers which I think are excellent EXCEPT when they are idle they hiss like crazy. So, I did an RMA on them and I got sent a set of Gigaworks G550. I am now torn as to whether or not I should open the box or keep it new and sealed, sell them and buy a set of Logitech Z-5500s! I am happy to keep the Creative set but I dont want to open the box, set them all up and then find that they hiss as badly as my current set.

Basically does anyone know if they hiss when idle and the same for the Z-5500s, do these also hiss when idle because tis VERY annoying.

Thanks to all

Okay i just bought these from Ebay and got a great deal on them now i'm womdering why they might have been so cheap. Anywho i set up everything and found out that the main subwoofer needs to connect to the sound card, now the existing audio cable i have wont fit into rear of subwoofer, or cables that came with box wont fit either need help please!! Worried?