If you get the Logitech Z-5500, those have been very nice for me so far. They're generally computer speakers, but you can plug in your 360/PS3 in one of two ways:
1) Optical In. Only issue is that there's only one Optical Port on the Z-5500, but you can always just manually move the cable from system to system. For an Optical Toslink cable, check Monoprice.com.
http://www.monoprice.com/products/p...=10229&cs_id=1022901&p_id=2764&seq=1&format=2
2) 3.5mm to dual RCA Adapter. If you move the switch on the back from 3-input computer surround to 3 seperate stereo connections, you can get 3 of these adapters and plug in your normal analog Red/White plugs into this.
http://www.monoprice.com/products/p...=10401&cs_id=1040107&p_id=2120&seq=1&format=2
My current setup is 360 through Optical, DirecTV, Wii and the TV itself through Analog.
I'm sure a HTIB can do the same thing, but I've got great results through these speakers.
Dell Home had these for $259.99 when I bought them. I also got 10% off through making it a PayPal purchase, that has probably since expired.
If you just want a slight improvement and don't really need surround, I had my Creative 2.1 computer speakers hooked up to my consoles before, and they were a huge improvement over the TV Audio, both on my Vizio and my old Sony CRT. You just need one of those 3.5mm to RCA Adapters.
Hope this helps!
