Which Martin Logan Speakers should I buy?

I love the sound of the Logans and am trying to decide between the Ascent and the Odyssey. My listening room is 20 feet wide and 14 feet deep, with an 8 foot ceiling. I enjoy home theater, but also listen to music quite a bit.

Also, how do I find a seller for a reasonable price used, now that the "wanted to buy" section has been eliminated?