I like Matt's suggestions. After all, I was just about to recommend Ascend and my good friend just got them, happen to own T55s, and helped someone else choose RS6. Hehe.
OP, if you have space for a vertical bookshelf do it. Ascend will sell individually. You can get 3x 170 SE's for about $500. Perfectly matched, no lobing issue. (Someone calculated for me that the matching PSB Image center's woofers would be 180 degrees out of phase at a 20 deg listening angle). And the better matching bookshelf centers usually cost less than the compromised horizontal type.
j