surround speakers to match Meridian P350W


I have a Meridian G68 processor, a G57 amplifier and a G55 amplifier, which will suffice to drive a 7 channel surround system. I started with buying 2 Meridian P350W (wall mount speakers) for stereo. Now I am looking to add a center, sub, rears and sides. Of course, I could add additional Meridian speakers. But other than Meridian speakers, what else would be a good match? I want the best possible sound for stereo and have spent the money accordingly. But I haven't heard much difference between expensive and less expensive speakers for a surround system. What would be a good solution?
axle
+1 Stick with Meridian for center and surround. All speakers should match as close as possible. You have matching amps and that will help too. Meridian center speakers have a particular feature that allows you to adjust your image 3 feet up or down. Install the speaker just below your screen and adjust accordingly. Slick!
For the center, you should stick with Meridian but you can experiment with the others.

Kal