Just read your post at audioholics, and to answer your last question about subwoofer hookup, no, you cannot use that type of adapter. Looks like your main objective is a home theater for a very large area. The Elac speakers do get good reviews, however they have a low sensitivity. A higher sensitivity speaker would be much better for your setup. The Hsu research bookshelf speaker gets very good reviews as well and has a 7db higher sensitivity. As far as matching speakers, take a look here.
http://www.soundandvision.com/content/matching-front-and-surround-speakers#GsU4hCQPZXlESVeL.97
http://avtruths.com/speaker.html
IMHO, the best sound is achieved with all identical speakers. If this is not possible, then at least use timbre matched in the same series. Definitely do not mix brands. It's ok if the subwoofer is a different brand, and in your setup, I would recommend two subs.
http://www.soundandvision.com/content/matching-front-and-surround-speakers#GsU4hCQPZXlESVeL.97
http://avtruths.com/speaker.html
IMHO, the best sound is achieved with all identical speakers. If this is not possible, then at least use timbre matched in the same series. Definitely do not mix brands. It's ok if the subwoofer is a different brand, and in your setup, I would recommend two subs.