This is exactly one of the reasons why I began this thread. The intended setup won't be just for me, but others in the family that aren't that techy, and I know wouldn't want to mess with a desktop interface on the big screen. And the truth is, I would want to keep it that way for myself as well.
I would rather stick to ATV's UI as the primary front UI for all the couch-family viewing/listening. I should have mentioned before that I have no specialized needs for additional, non apple formats. In fact I will only be streaming MP4s for video and MP3s and AACs for audio. Very simple. Nothing more. For that I think the ATV is perfect.
I think if you're not working with a Mac Pro or other power hungry PC desktop tower, than you might not want to consider a Mini? Simply stream the content from your laptops might be just good enough. I am just sort of dancing around the idea of a much more discreet and energy efficient machine to house that content and perhaps the contents of all Macs in the house, to stream, hence the Mac mini.
My idea of having a Mini as a companion to the ATV though, at least gives us the option of connecting it directly to the TV if you personally decide to do more than just front row stuff on the couch.
And again, I think $99 is a killer deal in my opinion. That's much easier to swallow than the previous $229 price tag.