I would definitely stick with ML in order to match the tonality and speed of your Summits... either the Stage or Motif. I have Summits with a Motif center and couldn't be happier.
matching center channel to mains/rears
I am getting a new HDTV, been out of home theatre for a long time. I need to pick up a center channel. My mains are Martin Logan Summitt's. I am looking to find an adequate center, as the "best" seems a tad pricey. Is there any loss in switching to a different brand of center, say going to a B&W? Also I'm using an old set of Vandersteen 2ci's for rears.