Need help deciding...

I just bought a creative surround station to bring my surround speakers from 12' from my ears to about 2'.
After hearing them clearly for the first time in about 2 years, it's obvious they are on the fritz, besides it's time for an update. I have a Yamaha RX-V463 5.1 receiver and a pretty good 12" Sony subwoofer, an X-Fi Platinum fatal1ty (which incidentally just TODAY got windows 7 drivers!). So I am stuck between a Klipsch 5.1 Promedia system or the Z-5500.
My main questions, are about which direction I should be heading:

1. Should I just bypass the Yamaha receiver even though it decodes DTS DDL and has Cinema DSP in favor of the integrated system with the Z-5500/Klipsch?

2. Would it be advisable just to purchase a 5.1 speaker system (or even just the 5 speakers since the sub is great) and hook them up to the receiver? If so what brand you suggest looking at?

I have about 250-350 to spend and my main uses are music and games, occasionally movies. Thanks for any help