I second the vote for monoprice cables.
However, I also use a 6' HDMI cable from Big Lots that I got for $9(the most expensive cable in my system BTW), about a year ago.
I am not familiar with that AVR, but I know that the Wii only uses Composite and/or Component connectors(unless you bought an aftermarket HDMI converter cable. So the question would be if the AVR offers up conversion to HDMI from Composite and/or Component.
I will leave that answer to the manual, or any owners in the know...