Bilbo, I recommend 7.2, if you're thinking about this path of audio madness, it's already too late, you're doomed, you're gonna do it, and you know it. Why stop at 7.1 when you can shake the house with twin subwoofers? If you want your subs talking to you in stereo, you can get an Outlaw ICBM-1 bass management module. It'll also give you full bass management control even in DVD-Audio or SACD and twin/stereo sub outs.

Enjoy the Music. Trust your ears. Laugh at Folks Who Claim to Know it All.