There is no such thing as "too much" for home theater.

Besides, that's what the volume knob is for. You can never have too much power on tap for a HT. There is nothing like watching something like "the lobby scene" from The Matrix at reference volume. Woo-hoo!
Many years ago, I spent a pretty penny on 5 Axiom brand speakers and a monster SVS subwoofer. They have served me well and I still have them. But knowing what I know now, I could built a better-performing system for about half what I spent.
Whatever you decide for mains/center/surround, just make sure they are all voice-matched. I.E. identical drivers. That is a problem many people make for themselves. When all 5 (or 7) speakers are not voice-matched a lot of "audible cues" are lost. I.E. if an on-screen character is talking while walking left to right you will be able to hear the difference in the voice as the sound moves from left front to center to right front speakers. If you know this already, sorry to bore you. If not, my job here is done.
