Can you ever have too much power?

Rogo - within reason you cannot have too much power. Amplifier-control of the speakers is one issue, headroom is another equally if not more important issue. My speakers are rated 100w/ch, but they consistently sound better with a 200w/ch amp, or more. Small amps, when overdriven, are what generally causes blown speakers. It is harder to damage a speaker by overdriving it with a big amp than with a small amp which is into clipping. If you occasionally like to crank it up then a larger amp is called for. If not then some of the issues raised above are indeed to be considered. I generally listen at only around 2w/ch, sometimes 20w/ch, sometimes more. At said 2w/ch level I have 100x that power level for an ideal 20dB of transient headroom.
Doubling or halving of power is a 3dB change, which seems like a lot but it isn't actually that much. Going from 1 to 2 watts = +3dB. 2 to 4 watts is +3dB. In the other direction, 100 to 50 watts is -3dB. 50 to 25 watts is -3dB.
for POWER:
1dB = 1.25x
3dB = 2x
6dB = 4x
10 dB = 10x
20dB = 100x

voltage (dBv) is measured differently however.

Bob bundus
Nicely articulated response.

Bob bundus. I agree with Jsteigert - That was a concise and ealsily understood response. And also with Nalu's closing analogy. A far better visual than mine. Thanks everyone.

Many Quad, Spica and others have suffered from too much power. Of course it was human error, but sans the power, their speakers might still be working.