Which is a better option?

I'm getting a new computer desk pretty soon and will finally have enough room to get 5.1 system. I'm not a big audiophile so I'm not sure which is the best option to go for. Right now I'm thinking between:

Z-906

or this combo

Pioneer VSX-520-K with Klipsch HD 500

I know that Z-906 isn't getting the best reviews but I'm also not sure how a custom setup will work on a PC. Let me know what you guys think.

Run SPDIF-out from the mobo/sound card to the Pioneer...along with that Klipsch setup. Thatll obliterate those Logitechs good.

Absolutely... ^^

I don't have SPDIF-out on my sound card (X-Fi XtremeMusic) but my mobo has one (Gigabyte UD-7 / 1155). Honestly I'm not even sure what kind of onboard audio my mobo uses but would it still be better then my sound card?

Looks like you can use the digital port with a mini to coaxial adapter to get it to the receiver. See the pic:

Just use an adapter like this and a standard 75ohm rca cable.