Im still looking for good 7.1 systems but i know of some good 5.1 systems if you want to consider them. I'll update my post when i find good 7.1 systems
Logitech G-51 if you can make it work $199.95USD
Creative Inspire T6100 $79.90 USD
Creative SBS A500 $99.95 AUD
EDIT: If ur budget can stretch REAAAALLLY far you can get the
Creative Gigaworks S750 for about $560 AUD lol