^^Co-signed. Also comes with DD/DTS decoders, so you can get 5.1 out of you're PS3.
Note though: S-pdif can NOT carry 5.1 unless its already encoded with Dolby Digital/DTS, unless Dolby Digitial Live is used to upmix the signal. As such, if you connect to you're PC via spdif, you will only get 2.0 sound. (Its a limitation of Spdif, not the speakers)
I recommend the following setup:
PS3->Spdif->Z5500 (5.1 via Dolby Digital/DTS)
PC->Analog 3.5mm->Z5500 (5.1 PCM)
BTW, can you hook both connetions for the Z5500 up at the same time?